The Castro District, commonly referenced as The Castro, is a neighborhood in Eureka Valley in San Francisco, California. The Castro is one of the United States’ first and best-known gay neighborhoods, and it is currently its largest. Having transformed from a working-class neighborhood through the 1960s and 1970s, the Castro remains a symbol and source of lesbian, gay, bisexual, and transgender (LGBT) activism and events.
San Francisco’s gay village is mostly concentrated in the business district that is located on Castro Street from Market Street to 19th Street. It extends down Market Street toward Church Street and on both sides of the Castro neighborhood from Church Street to Eureka Street. Although the greater gay community was, and is, concentrated in the Castro, many gay people live in the surrounding residential areas bordered by Corona Heights, the Mission District, Noe Valley, Twin Peaks, and Haight-Ashbury neighborhoods. Some consider it to include Duboce Triangle and Dolores Heights, which both have a strong LGBT presence.
Castro Street, which originates a few blocks north at the intersection of Divisadero and Waller Streets, runs south through Noe Valley, crossing the 24th Street business district and ending as a continuous street a few blocks farther south as it moves toward the Glen Park neighborhood. It reappears in several discontinuous sections before ultimately terminating at Chenery Street, in the heart of Glen Park.Source :http://en.wikipedia.org/wiki/The_Castro,_San_Francisco