On March 6, 1836, the siege of the Alamo comes to an end as Mexican forces take the mission. Early on February 23, Mexican forces under the command of General Antonio Lopéz de Santa Anna marched into San Antonio de Béxar to put down the Texian rebellion, including eliminating the Texians holding the Spanish Alamo Mission. Over the next several days, the Mexican force continued to grow to approximately and plan the assault on the mission. On March 5, 1,800 Mexican soldiers prepared to assault the Alamo and its garrison of ~185-250 men. The Mexican assault began quietly at 5:30 in the morning of March 6, advancing to within musket range of the mission's walls while the defenders slept in the wake of a reprieve from an artillery bombardment the night before. Despite inflicting heavy casualties on the assaulting force, the Texian defenders were driven from the walls. A small force attempt to break out through the open prairie but were cut down by Mexican cavalry that had been assigned to prevent any such escape. Meanwhile, pockets of defenders where quiet one by one by the advancing Mexican troops. By 6:30 a.m., the battle was over with nearly every Texian fighter dead or dying; however, the Mexican force had lost ~300-400 men in the assault. Among the dead were the commanders of the Alamo William Travis and James Bowie as well as American frontiersman and folk hero Davey Crockett. According to some accounts, five or seven Texians had surrendered but were soon after executed as no quarter was to be given. Several non-combatants who had taken refuge within the mission were allowed to leave. The bodies of the Texian defenders were ordered burned.

In the wake of the Alamo, Texian forces and their supporters rallied to seek vengeance for the fallen, crushing Santa Anna's hopes that the Mexican victory at the Alamo and numerical superiority would cause the Texian rebellion to falter. Instead, the forces of the newly-declared Republic of Texas (independence had been declared on March 3, while the battle was still on-going) took the Mexican force by surprise at the Battle of San Jacinto on April 21 and routed them. Santa Anna was himself taken prisoner the next day and soon agreed to withdraw all Mexican forces from Texas. In 1845, the Republic of Texas was annexed by the United States at the request of the Texas government which leads to the outbreak of the Mexican-American War the following year. At the war's end in 1848, a defeated Mexico gave up claim to lands that would become the American states of California, Utah, and Nevada as well as part of Colorado, Arizona, New Mexico, and Wyoming. Furthermore, Mexico was forced to recognize American sovereignty over Texas.