Wanderlust World Wanderlust World The United States did not pay a single sum to acquire these four states. Their incorporation happened through two distinct processes:
Texas was an independent republic (1836–1845) after winning independence from Mexico. It voluntarily joined the U.S. via annexation, approved by both the Texan and U.S. congresses. No payment to Mexico.
These territories were acquired after the Mexican–American War (1846–1848). Under the Treaty of Guadalupe Hidalgo, Mexico ceded them (plus Nevada, Utah, Colorado) to the U.S. in exchange for $15 million and assumption of $3.25M in Mexican debts to U.S. citizens—not a purchase of the states individually.
This was a war settlement/cession, not a direct purchase like the Louisiana Purchase or Alaska. The $15M was compensation for territory lost in war, not a negotiated sale price per state.