The Portolá expedition was a Spanish voyage of exploration in 1769–1770 that was the first recorded European exploration of the interior of the present-day California. It was led by Gaspar de Portolá, governor of Las Californias, the Spanish colonial province that included California, Baja California, and other parts of present-day Mexico and the United States. The expedition led to the founding of Alta California and contributed to the solidification of Spanish territorial claims in the disputed and unexplored regions along the Pacific coast of North America.

Saint Junípero Serra Ferrer, popularly known simply as Junipero Serra, was a Spanish Catholic priest and missionary of the Franciscan Order. He is credited with establishing the Franciscan Missions in the Sierra Gorda, a UNESCO World Heritage Site. He founded a mission in Baja California and established eight of the 21 Spanish missions in California from San Diego to San Francisco, in what was then Spanish-occupied Alta California in the Province of Las Californias, New Spain.