The Battle of Alkali Lake was a battle between the X-Men and the forces of William Stryker. The X-Men were also joined by Magneto and Mystique for the most part of this battle. In the end, Stryker's base at Alkali Lake was destroyed due to the bursting of the dam.
Despite it not being on US soil, William Stryker made Alkali Lake in British Columbia, Canada his headquarters in the early 1980s. It was there he constituted the Adamantium onto the bones of the Wolverine. Although he abandoned the base shortly after doing it, he once again populated it after the Battle of the Statue of Liberty. Extracting a fluid from the brain of his lobotomized son, Jason Stryker, William began to torture the captured Magneto for information on Xavier's School for Gifted Youngsters. With the use of the fluid, Stryker found out all he wanted to know. Using his fluid on Kurt Wagner, Stryker attempted to get the president of the United States assassinated in order to pass the Mutant Registration Act. However, Wagner failed to the task and went haywire. Stryker then kidnapped Cyclops, the leader of the X-Men and Charles Xavier in order to create a version of Cerebro. Using a mechanism in order to suppress Charles' telepathy, William had his son torture Charles while his men built a version of Cerebro with which he would have Jason manipulate Charles into killing every mutant on the planet.
After Stryker's men kidnapped eight children from Xavier's school, the Wolverine, Rogue, Pyro and Iceman left and joined up with Storm, Jean Grey and Nightcrawler. They were soon after joined up with Magneto and Mystique and prepared to storm Alkali Lake. Once they made it to the lake, they began to take out it's security members and rescue to the children. Wolverine killed Stryker's main mutant thug, Lady Deathstrike, while Jean fought a mind controlled Cyclops. However, her battle with Cyclops was catastrophic as it resulted in the dam of Alkali Lake being punctured. Magneto then, despite knowing his friend would be sacrificed in the process, changed Stryker's Cerebro so that it would kill all humans instead. Magneto then chained up Stryker and tied him to the dam, while he, Mystique and Pyro left the battlefield. However, Charles was rescued by Storm and Nightcrawler, with the bursting of the damn stopping the Cerebro. In order to help the X-Men escape, Jean Grey sacrificed herself. The X-Men then confronted the president of the United States and revealed to him Stryker's illegal operations on foreign soil.
Magneto began to construct an even larger Brotherhood of Mutants shortly after the battle, whereas Cyclops constructed the Danger Room in order to train his students against threats. Jean Grey survived her apparent demise, nuzzling herself into a telekinetic coccoon where her Phoenix personality took over her mind, turning her evil. All of these would lead into the Battle of Alcatraz.