Common law marriage—also known as marriage without formalities or informal marriage—is marriage without a wedding or marriage ceremony and without a marriage license. Some states recognize common law marriage under certain circumstances—such as when the parties agree to be married, live together (cohabit) after agreeing to be married, and represent to others that they are married (holding themselves out as a married couple).

Other states previously recognized common law marriages, but no longer recognize such marriages after a certain date on which the law was changed—usually by statute. In other states, common law marriage has not been recognized by the legislature in a statute, but the courts have recognized common law marriage in court opinions or case law.

Ohio does not recognize common law marriages created after October 10, 1991. However, the state does recognize common law marriages that were established before this date if they met the necessary criteria at that time. These criteria included the intention to be married, cohabitation, and holding out to the public as a married couple. For common law marriages established before the cutoff date, the couples are generally afforded the same legal treatment as couples with ceremonial marriages. It's important to note that while Ohio does not allow the creation of new common law marriages, it does recognize common law marriages from other states where they are legally established, due to the Full Faith and Credit Clause of the U.S. Constitution.