Don Castro Regional Recreation Area, Regional park in Alameda County, United States

Don Castro Regional Recreation Area is a regional park of the East Bay Regional Parks system in Fairview, California, in Alameda County. It lies about 48 metres above sea level, 17 km from Fremont, among hills rising to 172 metres, in a Mediterranean climate averaging 17 °C.

The lake and lagoon were created in 1964 when the Alameda Flood Control and Water Conservation District built a dam on San Lorenzo Creek. This engineering project transformed the land into both a recreational space and a protected area.

The park lies in Fairview, an unincorporated community between Hayward and Castro Valley, and takes its name from the Castro family's Mexican-era land grant, Rancho San Lorenzo. Don Guillermo Castro's adobe stood near the creek that still bears the family name. Visitors today see a suburban park where that ranching landscape once ran cattle.

Don Castro Regional Recreation Area lies in Fairview, an unincorporated community in Alameda County, roughly 17 km from Fremont and within the East Bay Regional Parks system. The terrain around the park is hilly, rising to about 172 m within 1.3 km, and the park itself sits at about 48 m above sea level. The climate is Mediterranean, with average temperatures near 17 °C and most rain falling between December and May.

Don Castro lies in Fairview, an unincorporated community in Alameda County, not in Hayward or Castro Valley proper. The Cebuano Wikipedia entry places it about 48 metres above sea level, with hills rising to roughly 172 metres within 1.3 km, and Fremont about 17 km away.