Yuma Crossing
Immediately after the Mexican–American War in 1848, the U.S. Army built Fort Yuma here to protect travelers from Indians raiding the area. It was the center point of conflict in the Yuma War of 1850–53. From 1864–1890, the fort and nearby facilities was the main army base to support the US Army's efforts to control the Indians throughout the greater southwest.
War of the Confederation
The War of the Confederation () was a conflict between the Peru-Bolivian Confederation and a coalition of Argentina and the United Restorative Army, composed of Chile and North Peruvian dissidents, from 1836 to 1839. The creation of the Peru-Bolivian Confederation under Andrés de Santa Cruz started a power struggle in southern South America, with Chile and Argentina independently invading the Confederation to protect their interests, fearing the potential political, military, and economic power of the new state. Argentina was defeated in 1837, but the conflict continued for two years until United Restoration Army victory following the Battle of Yungay, resulting in the dissolution of the Peru-Bolivian Confederation, the exile of Santa Cruz, and the restoration of Peru and Bolivia as separate countries.