Watsonville is a city in Santa Cruz County, California, in the Monterey Bay Area of the Central Coast of California. The population was 52,590 at the 2020 census. Predominantly Latino and Democratic, Watsonville is a self-designated sanctuary city.

Watsonville's land was first inhabited by an Ohlone nation of Indigenous Californians. This tribe settled along the Pajaro Dunes since the land was fertile and useful for the cultivation of their plants and animals.

In 1769, the Portolá expedition, the first Europeans to explore the area, arrived from the south, where soldiers described a big bird they saw near a large river. The story survived in the river's name, Rio del Pajaro (River of the Bird).

The Portolá expedition continued north through the area, camping at one of the lakes north of town for five nights, on October 10–14, 1769. Many of the expedition's soldiers had scurvy, so progress was slow. While the sick recuperated, scouts led by Sergeant Ortega looked for the best way forward. On the fifth day, Franciscan missionary Juan Crespi, traveling with the expedition, wrote in his diary, "This afternoon the explorers returned. The sergeant reported that he had gone ahead twelve leagues without getting any information of the harbor that we are looking for, and that he went to the foot of a high, white mountain range."

During the October March 10, the explorers first saw the Coast redwood tree (Spanish: palo colorado). A bronze plaque at Pinto Lake (now a city park) commemorates the event. On October 15, the expedition continued to the northwest past today's community of Freedom, camping that night at Corralitos Lagoon.

The area became part of the Spanish colonial province of Las Californias, and in 1804 the northern part was split off to form Alta California. The area's pasture lands were assigned to the Spanish mission to the south, in Carmel.

When Mexico gained independence, it took possession of Alta California. The Spanish missions were secularized in the 1830s, and the future Watsonville area became Rancho Bolsa del Pajaro, a land grant made to Sebastian Rodríguez in 1837. Under Mexico's more liberal land-ownership laws, immigration to the area from Europe and the U.S. increased.

In 1833, Governor José Figueroa granted Rancho San Andrés to José Joaquín Castro, who came to California as part of the 1776 Anza Expedition and later became patriarch of a locally prominent Californio family. His son, Juan José Castro, built the Castro Adobe, the only two-story hacienda in the area at the time. Today, the adobe is owned by California State Parks and is undergoing restoration to serve as the Rancho San Andrés Castro Adobe State Historic Park.