The Justice League of America took its cue from the Justice Society of America, a band of super heroes who had formed around the time of World War II. The original members (Green Lantern II, Black Canary II, Flash II (deceased), Aquaman and the Martian Manhunter) joined forces to defeat the invading Apellaxian aliens. The press and the public quickly embraced the heroes, and they decided to form a permanent alliance.
The first team's headquarters was in a secret mountain "sanctuary" in Happy Harbor, Rhode Island. As the League has grown over the years, they have had to relocate on several occasions, generally choosing a locale that would give them easy access should a threat arise. These locations have included a massive satellite base, a network of government-sanctioned embassies around the globe, and the current Watchtower, which is located on the moon and can be reached via futuristic teleporters.
When an invading horde of White Martians threatened to decimate the planet, it became clear that only a revamped Justice League would be able to defend her. While the JLA has been looked to as Earth's protectors for many years, never more so than now has it showcased the best and brightest heroes has to offer. Superman, Batman and Wonder Woman head a team of heroes so powerful, they have been compared to a Pantheon of Greek gods. In other words, we're in good hands.
Current Members:
Black Canary
Green Lantern John Stewart
Vixen
Zatanna
Doctor Light II
Firestorm II
Equipment:
The Hall of Justice
The Watchtower
The Javelin
Former Members:
Superman
Batman
Wonder Woman
Aquaman
Green Lantern Hal Jordan
The Flash II
Martian Manhunter
Green Arrow
The Atom
Hawkman
Phantom Stranger
Elongated Man
Hawkwoman
Firestorm
Red Tornado
Steel II
Vibe
Gypsy
Blue Beetle
Captain Marvel
Green Lantern Guy Gardner
Mister Miracle
Booster Gold
Rocket Red
Captain Atom
Fire
Ice
Lightray
Orion
Tasmanian Devil
Bloodwynd
Maxima
The Flash I
Animal Man
The Flash III
Power Girl
Metamorpho the Element Man
Crimson Fox
Blue Jay
Atom-Smasher
Obsidian
Amazing Man
Blue Devil
The Wonder Twins
Green Lantern Kyle Rayner
Tomorrow Woman
Green Arrow II
Aztek
Steel III
The Huntress
Oracle
Big Barda
Zauriel
Plastic Man
Antaeus
Hourman III
Nightwing
Hawkgirl
Jason Blood
Major Disaster
Faith
Manitou Raven
Manitou Dawn
Supergirl
Black Lightning
Red Arrow
Geo-Force
Supporting Cast:
Snapper Carr
Sue Dibny
Maxwell Lord
L-Ron
Yazz
Zook
Villians:
Darkseid
Despero
Lex Luthor
The Joker
Vandal Savage
Starbreaker
The Key
Neron
Asmodel
Amazo
Parallax
Kanjaro Ro
Ra's al Ghul
Doctor Destiny
The Burning
The Lord of Time
Neh-Buh-Loh
T.O. Morrow
Professor Ivo
Amos Fortune
Eclipso
Doomsday
Felix Faust
Plastique
Electrocutioner
Dr. Impossible
Solomon Grundy
Anti-Monitor
Imperiex
Mongul I
Mongul II
Villainous Teams:
Injustice League
The Secret Society of Super-Villains
The Society
The Injustice Gang
Crime Syndicate of Amerika
The Royal Flush Gang
The Cadre
Troika
White Martians
The Star Conquerors
The Demons Three