In the 1800s, as the United States expanded, thousands travelled well-worn trails on foot and horseback in search of land and opportunity, often at the expense of Indigenous Peoples.

The mid-1800s saw diverse groups moving into the American interior. While this fueled U.S. growth, it also displaced Indigenous peoples, whose struggles continue today.

The Mexican-American War saw the U.S. and Mexico fight over Texas between 1846 and 1848, leading to significant territorial changes and setting the stage for future conflicts.

The Treaty of Guadalupe Hidalgo in 1848 transferred 55% of Mexican territory to the U.S., and ignited a fierce debate over slavery in these new lands.

The Fugitive Slave Act of 1850 gave the federal government new powers to capture and return escaped enslaved people, but its failures intensified divisions between Northern and Southern states.