The National Park Service has made the Stonewall Inn on Sheridan Square in Greenwich Village and the nearby park a national monument, honoring the rebellion in late June 1969. The riots started early Saturday morning June 28, 1969. The site is near the Christopher Street subway stop for the #1 IRT train.
As I’ve noted in Chapter 2 of my first DADT book, I think I was at a church retreat near Orkney Springs, VA that weekend, on a regular weekend pass from the Army at Fort Eustis. But Kerry Lauerman had an article in the Washington Post today in the Style section, "Stonewall: You Had to Be There", link, and there are stories that it was catalyzed by the death of Judy Garland.
Note the newspaper accounts at the time.
CNN has a typical news story of Obama’s visit here.