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.

Oregon does not recognize common law marriages. While some states in the U.S. allow couples to be considered legally married without a ceremony or official license if they meet certain requirements, Oregon is not one of them. The state requires couples to obtain a marriage license and have a marriage ceremony to be legally recognized as married. However, Oregon does recognize common law marriages that were established in other states where it is legal. This means if a couple has a valid common law marriage from another state, Oregon will consider them married for legal purposes. It's important for individuals in Oregon to understand that simply living together and holding themselves out as a married couple within the state does not grant them the legal rights and responsibilities of marriage.