Mont. Code Ann. § 70-28-301

"Entry townsite land" means land upon which an entry was made on or before July 1, 1921, by a probate court of any county in the territory or state of Montana for a townsite and a patent for the townsite was issued by the United States to the probate court or judge under the provisions of an act of congress entitled "An Act for the Relief of the Inhabitants of Cities and Towns Upon Public Lands", approved March 2, 1867, or other and subsequent acts of congress relating to entering lands for townsite purposes.