Common law marriage is a legal concept that applies to couples who are in a relationship that has the appearance of a marriage, but hasn't been formally sanctioned by the state (such as by the issuance of a marriage certificate). A valid common law marriage typically confers both the benefits and obligations of a formal marriage.
Courts most often apply the rules of common law marriage in situations where one partner dies without a will and the other claims there was a common law marriage so as to inherit property under intestate succession laws. These laws automatically give a share of property to a spouse, but may not recognize an unmarried partner.
Whether a common law marriage exists depends on a number of factors. First and foremost, a state has to acknowledge the legitimacy of common law marriages. It if does, then the validity of the marriage will depend in large part on how the partners view the relationship, and how they act on that perception.
A couple's intent is a crucial element in determining the existence of a common law marriage. If they treat the relationship as a marriage, it's likely they'll meet this requirement. But that in and of itself isn't enough. The couple has to comply with their state's laws regulating marriage, regarding issues such as meeting the minimum age requirements, and having the soundness of mind (mental capacity) to enter into a marriage. And, of course, neither of them can be legally married to anyone else.
In addition to the above, the couple have to hold themselves out to the public as being married. There are any number of ways to do this, like opening up a joint bank account, or signing a document that says you consider yourselves to be married. Using the term "spouse" when referring to each other in public, wearing wedding rings, or using the same last name are some other possibilities. In short, both your actions and words form the basis of a common law marriage.
As to how long you have to live together for a common law marriage to become viable, that's up to each state to decide. Contrary to what many people believe, there's no universally established time period.
Note that some states have a statute of limitations when it comes to recognizing common law marriage. If a couple separate, and one of them wants to make a claim against the other (for spousal support, let's say), the claimant will have to petition the court to recognize the common law marriage. If this isn't done within the particular state's legally mandated timeframe, the claimant will be out of luck. Statutes of limitation can vary on a state-by-state basis.
There are only a handful of "common law marriage states". Some of them provide for common law marriage in their statutes, while others do so through court decisions. The common law states are:
Note that the District of Columbia, although not a state, also permits common law marriages.
Regarding the above list, there are a few things you should be aware of. In New Hampshire, the way the law is written, the state only recognizes common law marriage for estate purposes. In other words, the marriage doesn't legally exist until one of the couple dies, which then allows the surviving spouse to claim any inheritance.
In Oklahoma, the state statutes and state case law appear to clash as to the legality of common law marriage. The statutes, on their face, would seem to permit only formalized marriages. But despite the statutes' wording, the courts have upheld common law marriages. At this point, how this conflict resolves itself is up in the air.
In Rhode Island, the courts have made it very clear that they believe common law marriage is an "outmoded doctrine", and they have practically begged the legislature to abolish it. (Luis v. Gaugler, 185 A.3d 497 (2018).) So that situation is one to keep an eye on.
Some states that formerly allowed common law marriages, but eventually prohibited them, will still recognize those marriages if they validly existed prior to the prohibition date.
These states are:
Anyone can do a name change; you don't need to be married. In theory, many states allow you to legally change your name by usage only—meaning that you simply start using your new name, without any court action. However, practically speaking, because you don't have a marriage certificate, you'll need an official court order changing your name before you'll get government agencies and many private companies, such as banks and title companies, to accept your new name.
If you live together in a state that recognizes common law marriages, and you don't wish to be married, it's a good idea for you both to sign a living together agreement (sometimes referred to as a "cohabitation agreement") making it clear that you both intend not to be married and describing your plans for keeping property separate and/or joint and for waiving any right to ongoing financial support from one to the other if you do break up. If you use the same last name and/or mix property together, it's essential that you do this. Otherwise a court might later find that a common law marriage existed, which can affect property rights and in some states, the right to support.
If you have a legitimate common law marriage, and you move to a state that doesn't permit them, your marriage should still be valid. This is because the "full faith and credit" clause of the U. S. Constitution requires states to recognize marriages that were legal in the state where the marriage took place.
As to the subject of same-sex common law marriage, in light of the U. S. Supreme Court's decision legalizing same-sex marriage, in theory these couples should be accorded the right to enter into a common law marriage in those states that still recognize them. Check with a local family law attorney to determine your state's position on the issue.