The bill received its second and final approval from city leaders on Tuesday with an overwhelming 11 to 2 vote, putting the bill in the hands of Congress and President Obama. Congress, which has final say on all laws approved in the District, will have 30 legislative days to respond.

According to the mayor's schedule posted online, Fenty will sign the gay marriage bill at the All Souls Church, a Unitarian denomination, on Harvard Street.

Opponents of the law have called on members of Congress to block the law. Representative Jason Chaffetz, a Republican from Utah, has said he will introduce a resolution of disapproval. But passage in the Democratic-controlled Congress remains unlikely. A point even Chaffetz, a freshman representative, has conceded: “It's going to be exceptionally difficult because Democrats have us outnumbered by large amounts,” he told the Salt Lake Tribune Wednesday. “Nevertheless, we're going to try.”

The bill signing is expected to begin at 10:45AM.