I would also be interested to compare their rise in Europe, as well, but for the sake of keeping the question manageable and not dissertation/book level, let's stick to the U.S. for now.
Did these neighborhoods exist "under the radar" for a long time? Or was there mostly a gay diaspora that eventually ended up congregating in certain areas after certain criteria were met? If so, what were those criteria, and what changed to cause them to come about? What was public reaction like when people began to see these neighborhoods come about? Was it different in California from, say, Texas?
Metropolitan areas have always exposed the minorities to each other in sufficient percentages to encourage congregation. I'm certain several instances can be cited detailing examples of minority subcultures forming cohesive nuclei in dense population centers.
An example that is close to answering your question is the cohabitation & co-development of the heterosexual leather subculture in intimate proximity with the advent of homosexual nightclubs in the main American port cities at the time. Following WW2 a massive commingling of self identifying non-traditional sex-role Americans took place for the first time. Individuals who may have been raised to believe they were alone or abhorrent in nature encountered each other for the first time.
Had there been no official government actions taken against non-traditional servicemen, the exposure to subcultures in these major processing centers/ports irrevocably changed the American consciousness of human sexuality. Individuals may have elected of their own free will to remain with their newly discovered peers in these cities. However the government did take action against these servicemen, forcing their hand.
A type of not-honorable administrative service discharge, called "blue discharge" papers (due to their color) existed. Regardless of its initial intent these Blue Discharge papers were used disproportionately on black & gay servicemen. The servicemen identified as homosexual during-service were allowed to complete their terms during the war as were black servicemen. However at the conclusion of the war these blue discharge recipients were excised from service into the ports of Sanfrancisco, Chicago and New York.
Servicemen receiving the Blue Discharge paperwork were prohibited from receiving any veteran benefits, they were listed as undesirable in government published post war veteran guidebooks provided to major employers and their hometown recruitment center as well as their residence of record were notified of their undesirable status.
It is hypothesized that this services of events created a type of "forced migration" by these individuals into their ports of discharge.
Miller, Neil (1995). Out of the Past: Gay and Lesbian History from 1869 to the Present. New York, Vintage Books. ISBN 0-09-957691-0.
Even in these major metropolitan areas Homosexuals (ICD-Sociopathy), leather culture, S&M (ICD-10), etc were considered to be mentally disturbed under the International Classification of Diseases. Additionally these behaviors were illegal and police enforced periodic arrest sweeps in the more desirable areas forcing these two cultures into cohabitation along with racial minorities in red-light districts.
San Francisco spearhead the various movements to legitimize these subcultures likely because they were also the nucleolus for the 1950's Beat Culture. This movement drew liberal individuals from isolated rural communities primarily through the exposure of ideas through music & magazine publishing. The Beat Culture was accepting of the gay & leather cultures as well providing an outlet for disenfranchised heterosexual youth. Jack Kerouac's On The Road and Allen Ginsberg's Howl are examples of seminal works that identified San Francisco as cultural safe zone for minorities.
Additional reading:
Columbia Universities Stonewall Riots resource center collection of primary resources detailing the conditions of persecution in the red-light districts which contributed to the Stonewall riots.
Gay Histories and Cultures: An Encyclopedia providing summation of primary sources relating to Americas relationship between it's sexual subcultures and it's migration from illegal metal illness to acceptance, etc.
Well in NYC Clinton as a gay area is pretty new in the citys history. (mid 80s, and had a bunch to do with being cheap if not safe and parts of gay life happening on the docs near by) Before that it was the West Village and that had to do with cheap real estate and a bohemian and artistic community, and was a gay area going back to the 20s. This is where Stonewall is. Rely Aids changed so much of gay culture, In the late 60s early 70s there was a "We are here deal with" attude in much of NYC but in the late 70s early 80s brought out a "We are here and wont take your shit we have real problems" idea that was much more aggressive and vocal. It was when things like store front health centers and other parts of public gay life came in to being with no code words or camouflage. While there were under the rader places many if not most were gay run but Mob controlled.
Gay New York: Gender, Urban Culture, and the Making of the Gay Male World, 1890-1940 by George Chauncey (May 19, 1995)