The Castro's LGBTQ community has roots in an injustice. During World War II, the U.S. military discharged thousands of gay servicemen from the Pacific theater through San Francisco, often dishonorably, because of their sexuality. Many of those discharged soldiers and sailors, unable or unwilling to return to hometowns where their discharges would follow them, settled in the Bay Area. They found each other in bars, social clubs, and rooming houses, creating informal networks that would grow over the following decades. San Francisco did not become a gay city by accident -- the military created the conditions by concentrating discharged gay men in a single port city, then leaving them to build lives without institutional support.

Through the 1960s and 1970s, gay men moved into Eureka Valley in increasing numbers, drawn by affordable Victorian housing and a growing critical mass of LGBTQ residents. The working-class Irish and Scandinavian families who had populated the neighborhood for generations began moving to the suburbs, and the new arrivals renovated the Victorians they left behind. Castro Street between Market and 19th became the commercial heart of the new neighborhood. Bars, bookshops, and bathhouses opened. The Castro Theatre, a 1922 movie palace, became a community gathering point. By the mid-1970s, the transformation was complete enough that the neighborhood's identity was no longer in question.

Harvey Milk's camera shop at 575 Castro Street became the informal headquarters of gay political organizing in San Francisco. In 1977, Milk won election to the San Francisco Board of Supervisors, becoming one of the first openly gay elected officials in the United States. He served barely eleven months before being assassinated on November 27, 1978, along with Mayor George Moscone, by former Supervisor Dan White. The murders, and the lenient manslaughter verdict that followed, ignited the White Night riots. The Castro grieved, raged, and then organized with even greater intensity. Milk's legacy transformed gay politics from a matter of social tolerance into a question of civil rights.

The AIDS epidemic devastated the Castro in the 1980s. The neighborhood that had built itself on community and visibility watched as that same density and openness became vectors for a disease that the federal government was slow to acknowledge and slower to address. Memorial quilts appeared in windows. Funerals became a fixture of neighborhood life. The crisis forged bonds of mutual aid and political advocacy that would shape the national response to HIV/AIDS. Today the Castro remains one of the highest concentrations of same-sex households in the country, a neighborhood that has survived displacement, assassination, epidemic, and gentrification to stand as evidence of what a community can build when it has nothing left to lose.