If you feel you are in a Common Law Marriage, read the information on the Law Library of Montana website.
Per the last paragraph of the information, you may choose to make a Declaration of Marriage without Solemnization according to MCA 40-1-311 and file it at the District Court Clerk’s Office.
The fee for a Declaration of Marriage is $53 in cash. Checks, debit cards, and credit cards are not accepted. The Montana Marriage Application will need to be filled out and the Parties must provide a Declaration that complies with the requirements of MCA 40-1-311.
The parties and their two witnesses must sign the Declaration in front of the Clerk or a deputy. Both parties must be present and each must show a valid driver's license issued by any state. A valid passport, birth certificate, or state issued identification card can be used in place of a driver's license.
Click here for a sample Declaration.