Continental Expansion (1816–1860)
With the independence of the United States established, military efforts then focused on ensuring a dominant role on the continent, an idea which came to be known as “Manifest Destiny.”
Although the War of 1812 ended as a stalemate between the United States and Great Britain in 1815, the frontier war essentially continued into 1818 with the First Seminole War. After the War of 1812 came the Seminole Wars, the Black Hawk War, and the era of Indian removal.
The Texas Revolution was a war fought from October 2, 1835 to April 21, 1836 between Mexico and the breakaway province of Texas. In February 1836, Santa Anna led his army into Texas; delayed by the defense of the Alamo, he overwhelmed it and shot the prisoners. The Texans declared their independence on March 2, 1836. Sam Houston led a successful retreat, but other insurgents were defeated at Goliad; Santa Anna shot the prisoners. But he was defeated and captured at San Jacinto on April 21; Santa Anna signed a treaty recognizing Texas independence and its expanded boundaries. The government in Mexico City repudiated the treaty and vowed to subdue Texas, a position that led to the Mexican-American War with the United States in 1846.
In 1857 U.S. troops were sent to the Utah Territory to reassert federal primacy in the region in what became known as the Utah War.