Those living in states that OK their marriage will file state returns as married. The same goes for married same-sex couples living in Colorado, Missouri and Oregon, even though those three locales currently prohibit same-sex marriage in their states. Utah — which also doesn't permit same-sex marriage — allows couples to choose whether to file as married or single.
Legally married same-sex couples in other states, who will have to file as single, should plan on spending extra time on their tax returns. Since states typically base tax returns on federal tax returns, these couples may have to create "dummy" federal tax returns as single filers before they can complete their state tax returns.
See the map below to determine which states require married same-sex couples to file as married and which states still mandate single returns.
source: kiplinger.com
