Gay marriage supporters won victories in three states: Minnesota, Maryland and Washington State.
In Maine, Question 1 won by a margin of 54 percent to 46 percent, with 49 percent of precincts reporting.
In Maryland, NBC News projected Question 6 to pass 52 percent to 48 percent, with 93 percent of precincts reporting.
In Washington State, Referendum 74 also passed by 52 percent to 48 percent, reports the Associated Press.
However, Amendment 1 in Minnesota was behind 54 percent to 52, with 67 percent of state precincts reporting, reports the Minneapolis Star-Tribune.