Most states do not recognize common law marriages. The ones that do include Alabama, Colorado, Georgia, Idaho and Iowa. Others are Kansas, Montana, New Hampshire, Ohio and Oklahoma. Additional states recognizing common law unions are Rhode Island, South Carolina, Texas and Utah. The District of Colombia accepts them as well.
Each state recognizes common law marriages differently and most do not recognize them at all. While Georgia, Idaho, New Hampshire, Ohio, Oklahoma and Pennsylvania recognize common law marriage, they each have different stipulations on whether or not you can qualify for one. If you do not wish to automatically be considered married in some of these states, you have to state it in writing. In all other states that do not recognize common law marriages, there is no possible way to be married just by living together for a certain period of time.
States that do not recognize common law marriage, do, however, recognize couples as being married if they have previously qualified for a common law marriage in a state that recognizes it. In the states that recognize common law marriages, couples who have qualified for a common law marriage have either most or all the same advantages as couples who have obtained a marriage license, and in the event that they wish to separate, must get a divorce.