STATES THAT RECOGNIZE COMMON LAW MARRIAGE:
Alabama
Colorado
Georgia (if created before 1/1/97)
Idaho (if created before 1/1/96)
Iowa
Kansas
Montana
New Hampshire (for inheritance purposes only)
Ohio (if created before 10/10/91)
Oklahoma (possibly only if created before 11/1/98. Oklahoma's laws and court decisions may be in conflict about whether common law marriages formed in that state after 11/1/98 will be recognized.)
Pennsylvania (if created before 1/1/05)
Rhode Island
South Carolina
Texas
Utah
Washington, D.C.

If you live in a state that DOES recognize common law marriage:
If you live in one of the above states and you "hold yourself out to be married" (by telling the community you are married, calling each other husband and wife, using the same last name, filing joint income tax returns, etc.), you can have a common law marriage. This means that you are a legally married couple in every way, even though you never obtained a marriage license. If you choose to end your relationship, you must get a divorce, even though you never had a wedding. Legally, common law married couples must play by all the same rules as traditionally married couples. If you live in one of the common law states and do not want your relationship to become a common law marriage, you must be clear that it is your intention not to marry.

If you live in a state that does NOT recognize common law marriage:
There is no way to form a common law marriage, no matter how long you live with your partner.

State-by-staw laws for common law marriage:

Alabama: The requirements for a common law marriage are: (1) capacity; (2) an agreement to be husband and wife; and (3) consummation of the marital relationship.

Colorado: A common law marriage may be established by proving cohabitation and a reputation of being married.

Iowa: The requirements for a common law marriage are: (1) intent and agreement to be married; (2) continuous cohabitation; and (3) public declarations that the parties are husband and wife.

Kansas: For a man and woman to form a common law marriage, they must: (1) have the mental capacity to marry; (2) agree to be married at the present time; and (3) represent to the public that they are married.

Montana: The requirements for a common law marriage are: (1) capacity to consent to the marriage; (2) an agreement to be married; (3) cohabitation; and (4) a reputation of being married.

Oklahoma: To establish a common law marriage, a man and woman must (1) be competent; (2) agree to enter into a marriage relationship; and (3) cohabit.

Pennsylvania: A common law marriage may be established if a man and woman exchange words that indicate that they intend to be married at the present time.

Rhode Island: The requirements for a common law marriage are: (1) serious intent to be married and (2) conduct that leads to a reasonable belief in the community that the man and woman are married.

South Carolina: A common law marriage is established if a man and woman intend for others to believe they are married.

Texas: A man and woman who want to establish a common law marriage must sign a form provided by the county clerk. In addition, they must (1) agree to be married, (2) cohabit, and (3) represent to others that they are married.

Utah: For a common law marriage, a man and woman must (1) be capable of giving consent and getting married; (2) cohabit; and (3) have a reputation of being husband and wife.

Washington, D.C.: The requirements for a common law marriage are: (1) an express, present intent to D.C. be married and (2) cohabitation.