World War III was a global conflict on Earth, waged in part with atomic weapons, in which 600 million perished.
The war began in 2026 and was instigated by British traitor Colonel Edward Featherstone Green, a man sometimes called Colonel Philip Green.(FASA, ENT: "In a Mirror, Darkly, Part II")
The Siege of Las Vegas was a significant battle in the war. (DS9 short story: "Second star to the right...")
The initial nuclear exchanges were fired on May 1, 2053, as witnessed by the inhabitants of Vanguard L-5 colony. (TLE novel: The Sundered)
- This would seem to contradict the prior canon statements that the war ended in 2053.
The war ended in 2053, when what remained of the governments agreed the fighting had to end. A cease fire, and peace treaty was signed in San Francisco. (ENT: "Demons")
Human genius Zefram Cochrane was implanted with a pain-inhibiting chip because he couldn't cope with the horrors around him. (TNG novelisation: "Star Trek: First Contact")
In 2079, the nuclear fallout created a post-atomic horror where legal systems were almost abolished. Lawyers were literally killed off as per a suggestion in the play Hamlet. (TNG episode Encounter At Farpoint)
External links
World War III article at Memory Alpha, the wiki for canon Star Trek.