Support for same-sex marriage has been on the rise over the past 15 years. Across four Pew Research Center surveys this year, 48% of Americans say they favor allowing gays and lesbians to marry legally, while 43% are opposed. Just four years ago, in the 2008 election cycle, 51% opposed making same-sex marriages legal and 39% supported it.

While support has grown in all regions of the country, it is far stronger in some than in others. In New England, 62% favor same-sex marriage, while 29% oppose it. People in the South express greater opposition. A majority (56%) in the central Southern states such as Alabama, Kentucky, Louisiana, Oklahoma and Texas oppose same-sex marriage, while about a third (35%) favors it — amounting to a 27 percentage point difference compared with New England.

Attitudes toward gay marriage in the South are comparable to where the country as a whole was a decade ago.

In the mid-Atlantic, 57% favor and 34% oppose allowing gay marriage. Opinions among those on the West Coast are similar (54% favor, 37% oppose). In the Midwest, opinion is more evenly divided (46% favor, 44% oppose).

On Election Day 2012, ballot measures legalizing same sex marriage were approved in Maine, Maryland and Washington state. The recent gains come after years of electoral setbacks for advocates of same-sex marriage. More than 30 states have prohibited gay marriage by popular vote over the past 15 years. Read More

Michael Piccorossi  is director of digital strategy at Pew Research Center.