Stanislaus County, California

Stanislaus County ( ; Spanish: Condado de Estanislao) is a county located in the San Joaquin Valley of the U.S. state of California. As of 2025, its estimated population is 557,719. The county seat is Modesto.

Stanislaus County makes up the Modesto metropolitan statistical area. The county is located just east of the San Francisco Bay Area and serves as a bedroom community for those who work in the eastern part of the Bay Area.