Mont. Code Ann. § 70-22-207
Use of term Montana coordinate system limited
70-22-207 . Use of term Montana coordinate system limited. The use of the term "Montana coordinate system NAD 27 north, central, or south zone", "Montana coordinate system NAD 83", or "Montana plane coordinate system" on any map, report of survey, or other document must be limited to coordinates based on the Montana coordinate systems as defined in this part.