On Wednesday, Rhode Island became the 10th US state to pass same-sex marriage.
The state’s Senate voted 26-12 in favour of the same-sex marriage bill with the support of five Republican senators who announced their support on Tuesday.
Rhode Island Governer Lincoln Chafee, who supports the bill, is expected to sign it into law after it travels back to the Lower House for one final procedural vote expected as early as next week. A similar bill was easily passed in the Lower House in January.
Rhode Island was the last state in the New England region to allow gay marriage.
Supporters in Delaware and Illinois are hoping for a similar result later this year with coordinated efforts in New Jersey, Oregon and Minnesota.
The new law states religious institutions will still set their own rules on who can marry and no religious leader would be obligated to perform a ceremony for a same-sex couple.
Polls have shown support for same-sex marriage surge over the past 15 years. In 1996, a Gallup poll showed just 27 per cent of Americans backed marriage equality. Now Gallup finds 53 per cent of Americans support giving gay and lesbian couples the right to marry.
The new law takes effect on August 1.