A “gay bar” is a bar where “gay” (LGBTQ) people are welcome. “The swish-set back here is giggling about a cop in Yonkers, who makes the rounds of the gay bars there—not in line of duty—but as one of the ‘girls’” was printed in Walter WInchell‘s syndicated column in the Evansville (IN) Courier on October 15, 1951. “Q.—‘What is a gay bar?’ A.—‘Homosexuals’” was printed in the San Francisco (CA) Examiner on February 3, 1953. “Gay (homosexual) bar” was printed in the Salinas (CA) Californian on September 25, 1953.
 
   
(Oxford English Dictionary)
gay bar  n. a public house or bar frequented predominantly by homosexuals.
1947   K. Williams Diary 16 Jan. (1993) 9   Went round to the gay bar which wasn’t in the least gay and saw K. and Co.
1976   M. Machlin Pipeline xxxviii. 412   There were no gay bars or hangouts, and very few gays dared walk the streets in the more extravagant, deviant-type-wardrobes.
         
15 October 1951, Evansville (IN) Courier, “Broadway” by Walter Winchell, pg. 6, col. 3:
But this item is no foolin’: The swish-set back here is giggling about a cop in Yonkers, who makes the rounds of the gay bars there—not in line of duty—but as one of the “girls”...Waht kinda people is this???
     
3 February 1953, San Francisco (CA) Examiner, “Eichenbaum and Tenner Named By Witnesses in Tarantino Probe,”  pg. 4, col. 6:
Q.—“What is a gay bar?”
A.—“Homosexuals.”
   
25 September 1953, Salinas (CA) Californian, “Tarantino Pose ‘Reformer’ as Claimed” (UP), pg. 4, col. 5:
4. That Tarantino obtained a $100 ad that ran for many months from the operator of a Market street tavern under threat of running a “gay (homosexual) bar.”
 
15 October 1953, San Francisco (CA) Examiner, “Wrangle Over Testimony Delays Trial of Tarantino Until Oct. 26,” pg. 10, col. 4:
Davis said he was operating the Silver Rail bar, 974 Market Street, which he frankly admitted had been “a gay bar—one catering to homo-sexuals.”
 
11 April 1954, San Francisco (CA) Chronicle, “Tommy’s Place: Gaffney Asks Suspension Of Bar’s Liquor License,” pg. 3, col. 2:
Chief Gaffney told the heads of his narcotics, juvenile delinquency and sex details that he would assign extra personnel where needed to check up on the activities of Tommy’s Place, and other “gay” bars, catering to sex deviates.
   
OCLC WorldCat record
Memo from the Village Theater Center Books re: Gay Bar, April 15, 1958.
Publisher: [Place of publication not identified] : [publisher not identified], 0000.
Edition/Format: Book Book : English.
Summary:
Typed memo from the Village Theater Center Books regarding a previously enclosed copy of the book, Gay Bar, and a missing order of books
 
15 June 1958, San Francisco (CA) Chronicle, “Life and Love among the Beatniks” by Allen Brown, This World sec., pg. 4, col. 1:
It’s shacking up for weeks at a time with a Beach chick, or picking up homosexuals in gay bars, or bumming all the way to New York to see if that Greenwich Village chick is still as good as the memory.
   
Google Books
Checklist: A Complete, Cumulative Checklist of Lesbian, Variant and Homosexual Fiction in English
By Marion Zimmer Bradley
Library of Alexandria
1960
Pg. ?:
After escaping from a sadistic lesbian matron in the reformatory, Noreen works as a fake butch in a Greenwich Village Gay bar and tourist trap; ...
 
7 August 1961, Times-Leader, The Evening News (Wilkes-Barre, PA), Walter Winchell column, pg. 19, col. 2:
The vice cops closed a notorious gay-boy bar on 6th Avenue. Next day a window sign announced: “Close for Alterations.”
   
Google Books
East Asia 1963
Edited by Eugene Fodor and Robert C. Fisher
New York, NY: D. McKay
1962
Pg. 190:
This is Tokyo’s most famous “gay boy” bar — in short, the “hostesses” are all men of deviate tendencies. However, you don’t have to have queer ideas to go there.
   
Google Books
Pacific Pathways
By Stanton Delaplane
New York: McGraw-Hill Book Company
1963
Pg. 47:
Japan is pretty relaxed about the homosexual. You’ll find “gay boy” bars here as well as in the Shinbashi district in Tokyo. Lipstick and kimono.
   
Google Books
The New York Spy;
A discreet guide to the city’s pleasures
By Alan Rinzler
London, UK: A. Blond
1967
Pg. 375:
If this new policy holds, there may be increasing use of the gay bars as social centers for gay life, but at the present time the effects of years of entrapment and harassment have taken the gay bar out of the center of New York gay life.
 
OCLC WorldCat record
Mr. Kenneth’s nationwide gay bar guide.
Author: Mr. Kenneth.; Katzoff Collection (Brown University)
Publisher: Hollywood, Calif. : Ken Green Group, ©1968.
Edition/Format:   Print book : English
 
15 March 1968, St. Louis (MO) Post-Dispatch, “The New Films” by Myles Standish, pg. 3F, col. 1:
One beating is by a bunch of 20 or so lavender young men in a so-called “gay” Greenwich Village bar who wear huge rings and brass knucks and painted fingernails.
(The movie P.J.—ed.)
 
4 May 1968, Shenandoah (PA) Evening Herald, “Voice of Broadway” by Jack O’Brian, pg. 2, col. 8:
Several of the gay (homo) Greenwich Village bars have their female opposites (bulldikes) as bouncers.
 
OCLC WorldCat record
Social interaction in gay bars.
Author: Robert Michael Johnston
Publisher: 1972.
Dissertation: M.A. Northern Illinois University 1972
Edition/Format:   Thesis/dissertation : Thesis/dissertation : Manuscript   Archival Material : English
   
OCLC WorldCat record
The butch camp : a study of communication in two gay bars of Denver
Author: Jim Rudolph
Publisher: 1974.
Edition/Format:   Print book : English
 
OCLC WorldCat record
Gay times’ international gay guide : featuring complete listings of baths, gay bars, hotels, clothing stores, book stores, cruising areas, gay lib organizations, and all kinds of action in the U.S. and abroad : the most complete and up to date listings of all the gay guides
Publisher: [United States] : Gay Times, [1975]
Edition/Format:   Print book : English : 1975 edition
 
OCLC WorldCat record
Baby, you are my religion : women, gay bars, and theology before Stonewall
Author: Marie Cartier
Publisher: Abingdon, Oxon : Routledge, Taylor & Francis Group, 2014.
Series: Gender, theology, and spirituality (Routledge (Firm))
Edition/Format:   Print book : English
Summary:
Baby, You Are My Religion argues that American butch-femme bar culture of the mid-20th Century should be interpreted as a sacred space for its community. Before Stonewall-when homosexuals were still deemed mentally ill-these bars were the only place where many could have any community at all. Baby, You are My Religion explores this community as a site of a lived corporeal theology and political space. It reveals that religious institutions such as the Metropolitan Community Church were founded in such bars, that traditional and non-traditional religious activities took place there, and that religious ceremonies such as marriage were often conducted within the bars by staff. Baby, You are My Religion examines how these bars became not only ecclesiastical sites but also provided the fertile ground for the birth of the struggle for gay and lesbian civil rights before Stonewall.