The Mexican-American War marked the end of Spanish influence on the Pacific Coast.

The Mexican-American War (1846-1848) was a pivotal event that ended Spanish influence on the Pacific Coast. Following Spain's colonial rule, Mexico inherited its territories, including California and other western regions. However, after the United States defeated Mexico in the war, the Treaty of Guadalupe Hidalgo was signed in 1848, which led to Mexico ceding vast territories, including California, to the U.S. This treaty shifted the balance of power in the region, ending Spanish influence and establishing the United States as the dominant force on the Pacific Coast.