Mont. Code Ann. § 70-26-204

If a lessee of real property leased under an arrangement not governed by Title 70, chapter 24, remains in possession of the property after the expiration of the hiring and the lessor accepts rent from the lessee, the parties are presumed to have renewed the hiring on the same terms and for the same time, not exceeding 1 month when the rent is payable monthly, or in any case 1 year.