Common-law marriage, also known as non-ceremonial marriage, sui iuris marriage, informal marriage, de facto marriage, or marriage by habit and repute, is a legal marriage despite non-compliance with the prerequisites of a marriage license or participation in a marriage ceremony. The original concept of a common-law marriage is one considered valid by both partners, but not formally recorded with a state or religious registry, nor celebrated in a formal civil or religious service. In effect, the act of the couple representing themselves to others as being married and organizing their relation as if they were married, means they are married.

Here are some key points about common-law marriage:

• Common-law marriage occurs when two people who are legally capable of being married, and who intend to be married, live together as a married couple and hold themselves out to the world as a married couple.
• Common-law marriage is a legally recognized marriage between two people who have not purchased a marriage license or had their marriage ceremony.
• Common-law marriage is a legal marriage and an informal marriage.
• Common-law marriage is recognized in only a few U.S. jurisdictions, including Colorado, the District of Columbia, Iowa, Kansas, Montana, Rhode Island, Texas, and Utah.
• The requirements for a valid common-law marriage vary in each jurisdiction.

It is important to note that the term "common-law marriage" is often used incorrectly to describe various types of couple relationships, such as cohabitation (whether or not registered) or other legally formalized relations.