Mont. Code Ann. § 71-3-1302
71-3-1302 Purchaser's lien on real property
71-3-1302 . Purchaser's lien on real property. A person who pays to the owner any part of the price of real property under an agreement for the sale of real property has a special lien upon the property, independent of possession, for the part of the amount paid that the person is entitled to recover in case of a failure of consideration.