As of midnight last night, gay marriages performed in Connecticut, Massachusetts, Iowa, and for a brief time in California, will be legally recognized in the District of Columbia.

Gay activists hailed the development as an historic landmark for same-sex couples throughout the country and noted that it opens the way for the Council to pass a separate law later this year allowing same-sex marriages to be performed in the District.

“I think there’s tremendous significance and opportunity in Americans seeing legally married gay couples treated with respect in our nation’s capital,” said Evan Wolfson, executive director of Freedom To Marry, a national same-sex marriage advocacy group.

The recognition entitles gay couples to all the same legal rights extended to straight couples, including inheritance, and spousal immunity benefits.

And Maryland may soon follow. Governor Martin O’Malley on a radio program yesterday said he was open to having his state recognize gay marriage as well.