Marsha P. Johnson and Sylvia Rivera, pioneering transgender activists who were at the vanguard of the gay rights movement, will be immortalized in a monument that may be placed down the street from the Stonewall Inn, the city said on Wednesday.

Ms. Johnson and Ms. Rivera were both drag performers and vibrant characters in Greenwich Village street life who worked on behalf of homeless L.G.B.T.Q. youth and those affected by H.I.V./AIDS. They are also believed to have been key figures in the June 1969 Stonewall Uprising who fought police as they raided the gay bar on Christopher Street.

The planned monument will be publicly announced on Thursday in commemoration of the 50th anniversary of the uprising, which was a seminal moment for gay rights. It is also part of the city’s effort to fix a glaring gender gap in public art. Statues of L.G.B.T.Q. individuals are virtually nonexistent among the city’s monuments, and the city says the dedication to Johnson and Rivera will be one of the world’s first for transgender people.

The monument is proposed for Ruth Wittenberg Triangle, a short walk from Stonewall. In 1992, the city unveiled a set of statues in Christopher Park, across the street from Stonewall , by the artist George Segal to commemorate the uprising. The four figures, two standing men and two sitting women, are painted white and do not appear to depict particular people. Critics have said the sculpture excludes transgender women and women of color.