Castro Street Station is a Muni Metro station at the intersection of Market Street, Castro Street, and 17th Street in The Castro district of San Francisco, California. The station consists of two side platforms next to the tracks on the second level down with the concourse mezzanine level overlooking it. Uniquely among Muni Metro stations, the platforms are slightly curved due to the transition from the Market Street Subway to the Twin Peaks Tunnel between this station and the now disused Eureka Station, just southwest.