The universe of Apex Legends spans many planets in many star systems. They are divided into two regions: the Core Systems and the Frontier.
The Core Systems include Earth, its solar system, and other solar systems easily accessible from Earth. Little is known about the geopolitical state of these systems, except that these surrounding planets and systems are heavily populated and polluted, and that they have a lack of resources.
The discovery of the Frontier, a cluster of star systems with an unusually high number of habitable planets in 2292 by the Interstellar Manufacturing Corporation (IMC) sparked a "New Space Race" between the megacorporation and its various rival companies. This new Space Race was fought for a variety of reasons, most prevalent however was the immensely rich resources the planets in the Frontier possessed. IMC-funded colony ships were the first to colonize the region and the exploration and the colonization of the Frontier gave a major boost to IMC's support in the Core Systems.
Frontier colonization ramped up with the passage of the IMC Serviceman's Readjustment Act (the IMC's so-called "G.I. Bill"), which awarded veterans of IMC-backed military campaigns in the Core Systems various benefits; loans to start businesses and farms on the Frontier, low-cost mortgages and guaranteed property rights on Frontier worlds to start new lives. This new rush of settlers still had the combat skills they have acquired over the course of the conflict, including commandeering Titans.
In 2442, conflict erupted yet again in the Core Systems and this has led to neglect from the IMC of the Frontier settlers for centuries. This has allowed the development of the Frontier largely independent from the IMC, the growth of fiercely independent culture, and the rise of lawlessness in the area. The Corporate Wars eventually ended with the IMC as the victor.
Exhausted of resources from centuries of war, however, the IMC decided to return to the Frontier en masse and seeing the Frontier colonies thriving, declared eminent domain - citing their initial investment in the Frontier's colonization. Planets were seized and mining installations propped up at astonishing speeds, Frontier settlers meanwhile, were forcibly relocated or evicted from their homes. The various perceived injustices led to the formation of the "Frontier Militia", a confederation of various planetary armies, pirate and mercenary groups with one goal in mind: protect the Frontier and their way of life from the IMC.
The formation of the Militia and its subsequent attacks on IMC garrisons was what was presumably the reason for the start of the Titan Wars in 2671. The wars went on for twenty-one years and ended in the IMC's victory. Only fifteen years after this conflict, however, the Frontier War began. The Militia victory in the Battle of Demeter turned the tide of war and put the IMC on the defensive, cut off from supplies from the Core Systems, the remaining IMC forces limped on as the Remnant Fleet. The war eventually ended after the Battle of Gridiron, which left both the Militia and the IMC with no capabilities to wage more battles.
The current political status of the Frontier is unknown due to the communications blackout that occured immediately after the Battle of Gridiron.
Angelia is a planet in the Frontier.
The planet is home to Angel City, one of the first settlements in the Frontier and one of the largest cities to ever be on the Frontier. It was home to millions, if not tens of millions, of people. Angel City had a massive angel statue in its harbor, supposed to represent peace and unity across the Frontier. The company AI Logic, the parent company of Chevrex, was founded in the Harbor District of Angel City in 2445.
During the Frontier War, the IMC instituted martial law on the planet and constructed giant walls separating the districts of the city. Travel between districts was heavily monitored and the Harbor District's inhabitants weren't even allowed to leave their district.
At some point before the Battle of Demeter, the Frontier Militia went to the planet to retrieve a legendary pilot, Robert "Barker" Taube, supposedly "the guy that can fly anything." A battle ensued and the Militia was able to extract Barker, at the cost of many Militia infantry and pilots.
By 2734, Angel City has been mostly abandoned, with Valkyrie calling it a “ghost town”.
It is the home planet of Viper, as well as his daughter Valkyrie.
Cibus is a planet on the Frontier, in between the refueling planet Demeter and the major world Gridiron. A mountainous planet, with at least one moon and fauna that is very similar to that of Typhon, it is mainly used for refueling ships and was filled with refueling facilities and repair and refit stations. Although large, the planet's refueling facilities were a far cry from those of Demeter's.
Many of the refueling depots on Cibus were owned by the Dionysus Corporation, a subsidiary of the IMC. One of these was Black Water Canal. After the Battle of Demeter, the Remnant Fleet used the facilities to be able to travel faster around the Frontier, harass Militia fleets, and conduct resource raids on Militia planets and shipping lanes.
Demeter is a planet on the edge of the Frontier. Nicknamed "the Gateway", Demeter is the closest planet to the Core Systems, and was the first planet in the Frontier colonized by the IMC. As such, it contains major refueling stations and other infrastructure critical for ships making the journey between the Core Systems and the Frontier, so the journey takes only weeks instead of multiple years. Due to the significance and value of the planet, the IMC has stationed at least 1/3 of its entire Frontier naval capacity to defend the planet.
The planet orbits a dying red giant star, and has at least four moons. At least one of the moons is inhabited and has an IMC Air force base named Airbase Sierra. During the battle of Demeter, the base was attacked by the Militia in hopes of grounding a large portion of the IMC navy forces.
In the penultimate mission in Titanfall, the Frontier Militia attacked and successfully destroyed the refueling station, leaving the IMC forces stranded without backup. Five years later, during the Battle of Typhon, the refueling station has yet to be rebuilt, and IMC reinforcements have yet to arrive on the Frontier, although they promised that they would arrive in only 2 years. Due to the low number of IMC forces during those years, the Frontier Militia was able to take back over a quarter of the Frontier.
Eden is a planet in the frontier in the Yuma system, named due to its favorable Earth-like conditions. It has at least two moons and a ring system.
IMC marketing advertised the planet to colonists as the perfect place to live, filled with lush, verdant forests, and diverse wildlife. Many colonists moved to the planet, expecting a new life away from all the industrialization and pollution prevalent in the Core Systems, but once the IMC found massive fuel deposits in the planet's crust, everything changed. They started to establish massive mines and quarries, using methods like fracking to get access to untapped resources. After the industrialization of the planet, many of the natural environments like the large forests became deserts, and many species of flora and fauna alike became endangered or extinct. The mining industry on the planet displaced many of the residents and many of the cities became largely abandoned, with most of the population being IMC contractors and mechanized workers. Due to the fracking, the planet has become geologically unstable, causing massive earthquakes and ripping the landscape apart. The massive fault lines formed from these earthquakes created mountain-like structures that soar through Eden's sky.
- Arcadia Heights - located in the Meng Desert.
Gridiron is a desert planet. It appears in Titanfall as an IMC-controlled planet that is heavily terraformed, although it is still blanketed in its home star's radiation, making it unsafe, and possibly even lethal, to stand on its surface for more than a few seconds. A particularly nasty stomach bug is also known to be found on Gridiron. 
The planet has a population of 90 million and is the most populous planet on the Frontier to date. The only known city on the planet is New Anchorage. Before the Battle of Gridiron, the planet had an IMC base named Training Ground Whitehead, and many aspiring pilots went to the base to train. The base was protected by a 400-mile no-fly zone, and unauthorized vehicles detected in the area were either shot down or signaled to leave before the IMC used lethal force on the incoming vehicle. At about 100 miles away from Training Ground Whitehead, there is an abandoned reservoir that has been converted into a Militia covert listening post named Rise. The Militia used the base to spy on the nearby IMC base and intended it to be used as a staging point to attack Training Ground Whitehead. At some point after the Battle of Demeter, but before the battle of Typhon, the IMC detected the base and launched an attack on it, with a battle soon ensuing between the Militia and IMC forces.
Gridiron was the site of the last battle in the Frontier War. The battle is assumed to have resulted in a Militia victory, though both factions seemingly disappeared afterward and left the war-ravaged Frontier to govern itself.
Travel from Gridiron to the Outlands takes roughly twenty years without access to a Jump Drive or high quality fuel.
Harmony is a planet in the Freeport System. The planet has at least one moon and had an overall population of over 40 million inhabitants. Harmony's main industry is farming, with its landscape mainly being farmland with odd towns scattered in between.
After the Battle of Demeter, Harmony became the Frontier Militia's headquarters and was the target of resource raids by the IMC's Remnant Fleet. Due to its status as the core Militia world, it was also the IMC's main target for the Fold Weapon.
Harmony is the homeworld of the legendary Militia pilot Tai Lastimosa.
- Nexus - A small farming town that was attacked by the IMC during the Frontier War at some point after the Battle of Demeter.
Leviathan is a planet in the Badlands system. It is the homeworld of the gargantuan creatures also called Leviathans. There have been theories that much of the other alien fauna found across the Frontier, such as the reptilian Prowler, the large dragon-like Flyers, and even the hulking Goliaths, also came from this planet.
Leviathan is mainly desert, with multiple humid swamps. These planetary conditions are hospitable for humans, though the local wildlife is not. The population of the planet has depleted to less than 100,000 due to its extremely hostile wildlife. To combat this, IMC scientists created the Repulsor Tower. This new technology kept the wildlife away from cities and IMC facilities. One of these facilities, named Base Golden, was used to create and test the Repulsor Towers used all over the Frontier. The base was abandoned by 2690, and during some point after the Fracture Operation, the base was a site of a battle. The Militia was trying to download information on how the Repulsor Tower worked so they could re-engineer the technology to create the "ice pick", which would be used later in the Titanfall campaign.
Troy is a planet in the system dubbed Sector Bravo-217, near the Yuma system.
The planet was previously unknown and unexplored by the IMC, and it stayed untouched until the Titan Wars, when the IMC ship IMS Odyssey mutinied against the IMC and decided to land on the planet, away from the IMC's grasp. The crew established a colony they called Colony G21, with a population of about 94. Around 15 years later, after the Fracture Operation, a Militia fleet detected a signal coming from the system, a distress call coming from the colony due after an IMC attack. After both fleets arrived in the system, a battle ensued and the former IMC legend James MacAllan, previously neutral, sided with the Frontier Militia. After the First Battle of Troy, many colonists had been either killed during the battle or captured by the IMC. Those captured were transported to an unknown location to be tested on by the ARES Division, specifically General Marder. At some point in time after the Battle of Typhon, the colony seemed to have recovered from the first battle, but was attacked again. It is unknown what became of the colony after the Frontier War. The terrain of the planet is very mountainous and yet tropical. It is unknown exactly how the tropical climate, the massive mountains, and the gaping canyons came to be, but it is suspected that acidic rivers carved the canyons out from the rock.
Typhon was a planet in the Frontier. It was Wraith's home planet, and the site of the campaign of Titanfall 2. It had at least one moon, Orthros, which was shattered by the IMC during the testing of the Fold weapon.
It was the site of at least one ARES Division research laboratory, most likely focused on the huge installation ARES dubbed the "Fold Weapon", a relic left behind by an advanced alien civilization that is presumably extinct. When the Militia found out about the Fold Weapon, they sent in the 9th Militia Fleet, and a large battle ensued. During the end of the battle, pilot Jack Cooper caused the Fold Weapon to backfire, destroying Typhon. This happened because his Titan, BT-7274, sacrificed himself to save the Militia planet Harmony, the main target for the fold weapon.
Before the Battle of Typhon, genetic experimentation was conducted on Medusa vines. The experiment was called Project: LEGACY. The end result of the experiment produced a new species of Medusa vine that grows rapidly, is almost impervious to damage, and releases deadly pollen. When exposed to humans, this pollen causes symptoms that include bleeding from the eyes and eventually death 72 hours after symptoms first appear. 18 years after Typhon was destroyed, around 2733, a salvaging fleet called the Icarus Fleet, the flagship being named the Icarus, entered the system to salvage what was left in the wake of the massive battle that had occurred there. During salvaging, they came across the modified Medusa vines. Somehow, the vines infiltrated every ship and killed all the crew. In 2734, they entered Psamathe's system when the Icarus docked in Olympus, a city on Psamathe.
Victor is a planet in the Frontier in the Yuma system, the same system Eden is located in.
This planet was once as verdant as Eden, and IMC marketed Victor just as they had Eden. Because of this campaign, many cities were built on Victor, and the planet became known for its wealth. As they had done on Eden, however, the IMC discovered massive fuel reservoirs deep beneath Victor's crust. So, the IMC began mining the planet, using methods that placed the residents in danger. For instance, the IMC's use of fracking seismically destabilized many areas of the planet. Because of this, the IMC decided to evict much of the population, if they hadn't already left on their own due to the numerous dangers on Victor. The wealthy abandoned the planet early, finding ways to escape the unstable planet. At some point before the Battle of Demeter, the 1st Militia Fleet of the Freeport Brigade raided some of the fuel depots in an abandoned city on Victor, but suffered heavy casualties because the IMC had known about the raids beforehand. During the battle, rifleman Jack Cooper was deployed and suffered a head injury. After the battle, Jack to forgot the entire thing due to amnesia. The battle became known as the "Fracture Operation".
The Outlands is a small cluster of planets on the fringes of the Frontier. Travel from the Core Systems to the Outlands takes roughly 20 years.
Initially colonized in the 2300s, the Outlands was controlled by the IMC for most of its history, primarily because of its military and mining outposts. From 2713 to 2719, the IMC began to retract from the Outlands to focus its efforts on the Frontier War. The withdrawal and the ensuing power vacuum it created ignited a civil war between these planets in 2716, only ending in 2723 with the signing of the Mercenary Syndicate Treaty. The six planetary governments who signed the treaty were then organized as "Syndicate Space", formally referred to as the Syndicate Alliance of Free Worlds,  ruled by a group calling themselves the Mercenary Syndicate. The rest of the planets of the Outlands became known as the "Fringe Worlds".
One of these Fringe Worlds, Salvo, formally joined Syndicate Space in 2734 after more than a decade of resistance.
Boreas is a planet in the Outlands. It has a robust textile industry, which leads to a ubiquity of moths throughout the planet’s culture, traditions, and even their superstitions. A famous folktale, "The Moth and the Flame” is well known on the planet. In 2708, a meteor struck its moon Cleo and shaved off a significant portion of said moon's landmass. The rapidly deteriorating condition of the moon is stated to cause regular meteor showers on Boreas' surface and atmosphere, disturbing changes in the planet's tides, rising temperatures at the poles, and plummeting temperatures at the equator. Reports had stated that if nothing is done, Boreas will be unlivable in 50-70 years.
It is the home planet of Seer.
- Cleo - Boreas' moon. Parts of it was destroyed when a meteor struck it in 2708.
- Chikuum - One of the planet's larger cities. Home of "The Foundry Arenas", where Seer participated in many Arenas matches. The "Encore" arena is located there.
Gaea is a planet in the Outlands with a large urban population, although most of the planet's population live on farms. Like Psamathe, it also has its own police force, the Gaea Global Task Force, who are infamously ruthless. Likewise, their leaders are said to be very tyrannical.
- New Antillia - a gorgeous tropical archipelago made up of multiple micro-islands, home to pristine beaches and exotic wildlife. Most of the islands serves as resorts, but some places are off limit to public.
- Storm Point - A long-forgotten IMC research base located on a tropical island teeming with dangerous wildlife, off-limits to the public; now a stage for the Apex Games. Storm Point was additionally the crash site of the IMS Hestia 01, which Bangalore and her brother Jackson served on. 
- Habitat 4 - One of the smallest islands in the chain, best known as a Leviathan breeding ground with a large population of local Leviathans. Name designated by Early IMC research groups.
- Tribulation Isle - An area off-limits to the public.
- Hana Beach - Another area off-limits to the public.
- Amelia Mountain Range - Wild jungle area which is home to the Carthage spiders, a Mammoth-class arachnid that releases an extremely toxic gas when in danger or hunting.
- Styx - A jungle where mammoth-class arachnids reside.
- Suotamo - One of the largest cities in the Outlands. Known for its resemblance to Angel City, including a similar angel statue. Ticacek Orphanage is located here and is where Crypto grew up.
- Zaldana City - Former home of Humbert Labs, where Alexander Nox was supposedly found dead.
- Hollygrove - Caustic's birthplace
The planet is, in theory, ruled by an oligarchy of the richest residents, in which the head of the most powerful families participates in a governing council; in practice, it is more of a diakology, with the family instead sending representatives that are under their employ. Although it has no official military, there are numerous personal armies owned by citizens.
In 2734, a scavenger fleet from Typhon (later found to be sent by Torres Silva) entered the atmosphere of Psamathe carrying a modified version of the Medusa vine, spreading a contagious illness which infected the city of Olympus. It is the home planet of Lifeline, Octane, and Horizon, as well as where Pathfinder was created.
- Olympus - A floating city in the sky, now a stage for the Apex Games.
- Malta - A metropolitan city on the ground drenched in smog. Fight Night takes place here, as does the Season 7 Quest, Family Portrait. Malta contains the automated Hammond Manufacturing Tower, codenamed Drop-Off, which was used for early production of components for Olympus. The Tower serves as a factory by day and an Arenas site by night.
- Dionysus - Psamathe's moon. A "resort moon" for people to live their richest fantasies. An extremely exclusive getaway destination.
Salvo is a planet that was formerly one of the independent Fringe Worlds. It has recently come under the leadership of Sandringham Kelly, agreed for Salvo to become the seventh planet in Syndicate Space.
Before Syndicate rule, the planet was a constant warzone with warlords assuming control of the planet, only to be overthrown by another warlord, and so on. The planet seems to have been in a perpetual state of war for at least 50 years. At some point, Salvo was invaded by the IMC, with the corporation leaving behind several arms bunkers which continue to be raided by the warbands of Salvo. The matter of Salvo joining with the Mercenary Syndicate has been highly contentious among the populace, with a vast number of Salvonians violently resisting Kelly's rule and partnership. 
Salvo's leadership often shifts between various warbands and warlords. Two of the most prominent of these are the Black Rattler, led by Kelly, and the Cracked Talons, led by Mad Maggie.
Salvo's culture heavily revolves around violence, freedom, and resistance. One key example of this lies in the Bonecage, a brutal free-for-all brawling competition that acts as the planet's most popular bloodsport.  Salvonian culture additionally has a right of passage known as the Warrior Rites, where children become initiated as Salvonian fighters. It culminates in the Warrior's Feast, consisting of leviathan steak and couscous cakes. 
- Matakana - A coastal region. Fuse nearly drowned off the coast of Matakana once, but was saved by Maggie. 
Solace is a desert planet in the Outlands, considered to be the center of the Outlands because of its location in between most other Syndicate planets. It is infamous for its lawlessness, and was one of the planets hit hardest by the energy crisis. Even its morgues tend to not have regulations or protocols. Unclaimed dead bodies on Solace are typically buried after two weeks.
Solace was previously controlled by the IMC as a research and development outpost, being the first planet in the Outlands they established themselves on and the last one they left. Solace now falls under Syndicate jurisdiction and also houses Syndicate Tower in Solace City. 
- Kings Canyon - Formerly an IMC military base on the Duchess River, now a stage for the Apex Games.
- Kómma - A former IMC-controlled city that once thrived with gambling, clubs, and various questionable activities. In the present day, Kómma is now a ghost town. When Mirage crashed the Mirage Voyage into its downtown plaza, he struck a deal with its current owner, allowing Ash to convert it into the arena "Party Crasher".
- Solace City - One of the only large cities on the planet, positioned near the coast of the Nostos Ocean. Solace City is considered to be a hub for fans of the Apex Games, with Loba regarding it as "an Apex theme park." During the energy crisis, Solace City used most of the planet's resources. Home of Mirage and his bar, the Paradise Lounge. The headquarters of the Mercenary Syndicate, Syndicate Tower, is also located here.
- Eelhead Bay - A fishing village that became part of Solace City. Home of Wattson.
- Little Mouse - A small town 10 km outside of Solace City, and home of Gibraltar's family since Solace was first colonized.
- Harris Valley - A small, idyllic town somewhere on Solace, Harris Valley was founded by those widowed, orphaned, and left behind by the IMC during the Frontier War, resulting in heavy anti-IMC sentiment. It is a peaceful area, not even needing a government or police force. The people of Harris Valley idolize a local hero named Newcastle. Unbeknownst to them, the original bearer of the mantle of Newcastle sold the town to a gang called the Forgotten Families, a group of IMC-loyalists, to pay off his debts. Home of Jackson Williams.
- Antheia - A region north of Kings Canyon. Nothing is known about Antheia other than its name.
Talos is a volcanic planet in the Outlands. Initially deemed uninhabitable, after the discovery of a rare mineral compound, the IMC invested in cooling towers to make the landscape hospitable. Today, the planet falls under Syndicate jurisdiction and contains a vast, untamed wilderness, holding various resorts used by the wealthy elite of Psamathe. 
It is the home planet of Bloodhound.
- World's Edge - Formerly an IMC mining outpost with the Capital City at the center, now a stage for the Apex Games.
- Phase Runner - A prototype phase runner located at the peak of a mountain, now an arena for the Arenas Mode.
- Hephaestus Station - Commonly known as Overflow, it is an automatic Branthium-processing station located among magma flows. Now it's also used as an arena for the Arenas Mode. 
- Bloodhound's village - A small community of hunters who spurn modern technology, located near World's Edge.
Tartarus is a Syndicate planet. It is a very dangerous and mysterious planet, and even the most adventurous residents of the Outlands hesitate to approach it. Little else is known about it. 
These are the planets of the Outlands that have not joined Syndicate Space.
- The Outlands are sometimes treated as separate from the rest of the Frontier. Senior writer Ashley Reed explained that this is because the Outlands were not as affected by wars or the Blackout as most of the Frontier was. The Outlands were initially a remote section of the Frontier, but now it acts distinctly from the rest of the Frontier thanks to more favorable circumstances.
- Pathfinder's Quest - Chapter 1
- Stated in The Art of Titanfall
- From Pathfinder's Quest, chapter 5
- From Pathfinder's Quest, chapter 2
- Stories from the Outlands - Judgment
- Loading Screen - Deep Dive
- Loading Screen - Lunar Impact Report
- Pathfinder's Quest - Chapter 8
- Loba's story page: A Mother's Advice
- Stories from the Outlands - Gridiron
- Tom Casiello on Twitter
- Tweet from @PlayApex
- Transition - Margaret Kōhere's Lessons
- Season 12 Loading Screen - "The Warrior's Feast"
- Season 7 Quest - Family Portrait - Page 5: "The Happy Ending"
- Season 9 Loading Screen - "Pour One Out"
- The Williams Sendoff Chapter 1 - "Living With It"
- Apex Legends Legacy Gameplay Trailer
- Stories from the Outlands - Hero
- Enter a New Arena in the Thrillseekers Event
- From Pathfinder's Quest, chapter 6
- Season 12 Loading Screen - "The Capture of M. Kōhere"
- ashsmashreed comments on Official Apex Legends: Legacy Update AMA with the Respawn Team