U.S. annexation of Texas

The annexation of Texas occurred in 1845 when the United States officially incorporated the Republic of Texas, which had gained independence from Mexico in 1836. Texas wanted to join the U.S. due to economic benefits and security, but Mexico opposed this move, leading to tensions. The annexation strengthened American territorial expansion but also contributed to the outbreak of the Mexican-American War. It marked Texas becoming the 28th state and reflected broader themes of westward growth and shifting borders in 19th-century America.