As of 2015, states that allow couples to contract common-law marriage include Alabama, Colorado, Iowa, Kansas and Montana, according to Unmarried Equality. Others include Rhode Island, South Carolina, Texas and Utah. The District of Columbia also allows common-law marriage contracts. Requirements for valid common-law marriages vary by state.
According to Unmarried.org, Most states require each person entering a common-law marriage to be old enough to consent to the marriage and to represent themselves as a married couple to the public, states Unmarried Equality. Common-law marriages in Utah must be validated by a state court, explains the Utah State Law Library.
Common-law marriage is not legal in New Hampshire, but the state does recognize it during probate for inheritance purposes, notes Unmarried Equality. Ohio recognizes common-law marriages entered into before October 1991, and Idaho recognizes common-law marriages entered into before January 1996. The state of Georgia acknowledges those created before January 1997, and Pennsylvania recognizes ones created prior to January 2005.
Common-law marriage is controversial in Oklahoma, notes About.com. State law only recognizes common-law marriages created before November 1998, but some state courts have validated some common-law marriages created after that date. Mississippi, Michigan, Indiana and South Dakota recognize common-law marriages created before 1960, and Florida acknowledges common-law marriages entered into before 1968, according to Wikipedia.