Xavier Cruz and JP Gomez, a married gay couple, knew discrimination against the L.G.B.T.Q. community had become widespread. But as owners of Barba Grooming Boutique, a salon in Manhattan, they thought their industry was largely immune.

So in 2016, when they read a story about a trans man suing a California barbershop for denying him a haircut, they were spurred to action: With the help of Terri & Sandy, an ad agency, the two set up Strands for Trans, a nonprofit group that maps salons and barbershops that have explicitly pledged their support for transgender clients.

Mr. Cruz, 55, and Mr. Gomez, 37, initially called locations in New York asking if they would join, receiving some welcome publicity from their friend the fashion designer Marc Jacobs. But finding businesses in some areas proved more challenging. After two weeks (and hundreds of calls), the couple was able to recruit at least one member in each state.

Now, eight years later, Strands for Trans has expanded its membership to more than 4,900 locations across the United States, as far-reaching as Deep Cuts, in Duluth, Minn., and Goldenrod Parlor, in Gainesville, Fla.

Kai, 14, travels about an hour with his parents for his haircut at Goldenrod. It’s not for a lack of competent local barbers in Columbia County, Fla., where he lives; rather, Kai was in search of a stylist better attuned to the needs of trans boys like him — and he didn’t want to return to the one who had given him a style more suited for a middle-aged woman.