History thumb|left|The Castro Adobe, built by Juan José Castro on Rancho San Andrés, is the oldest building in Watsonville. 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.
History thumb|left|The Castro Adobe built by Juan José Castro on Rancho San Andrés is the oldest building in Watsonville 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