The Battle of the Alamo took place in 1836 at the Alamo in what is now San Antonio , Texas , United States . The Battle of the Alamo ( February 23 â `` March 6 , 1836 ) was a pivotal event in the Texas Revolution . Following a 13-day siege , Mexican troops under President General Antonio LÃ pez de Santa Anna launched an assault on the Alamo Mission near San Antonio de BÃ xar ( modern-day San Antonio , Texas ) .