Yes, but...
Common law marriage, if your state allow it, is a legal marriage with all the benefits and all hassles, just with no formal ceremony, and that includes filing a joint tax return. And, once you have a common law marriage in a state that allows it, you are considered married even if you move to a state that does not have a common law marriage.
However, because common law marriage is a real marriage, if you break up, you have to go to court and get a real divorce. You can't turn a common law marriage on and off when you want to.
To have a common law marriage, you must generally do four things:
1. Live together and act as if you were married
2. Have a shared intention to be married.
3. Tell other people you are married.
4. Not be in a situation where you can't legally be married (such as, you are married to someone else and not divorced yet).
So it comes down to, do you meet those tests on or before December 31, 2024? If yes, then you can file as married. #3 is sometimes the tricky one, even if you think you are married, but you tell other people that your partner is your boyfriend/girlfriend/fiancee, instead of telling other people they are your spouse, then you might not meet the tests.
