Mont. Code Ann. § 70-1-106
Real property defined
70-1-106 . Real property defined. Real or immovable property consists of:
(1) land;
(2) that which is affixed to land, including a manufactured home declared an improvement to real property under 15-1-116 ;
(3) that which is incidental or appurtenant to land;
(4) that which is immovable by law.