No. Montana State Library states its statewide parcel and public lands GIS—the MSDI Cadastral parcel program—is for informational use only—not for legal, engineering, or surveying purposes. Polygon boundaries can lag deeds, split lots, exempt transfers, or rural fence lines.
Separate rules apply for Wilderness, national parks, grazing closures, firearm restrictions, motorized travel, closures for wildfire safety, leased state trust parcels, tribal boundaries, nuances of enrolled Block Management parcels, conservation easements, and local ordinances.
MSL maps easements voluntarily recorded between landowners and qualifying agencies or land trusts on private parcels. Showing an easement does not grant public recreation rights—consult the steward organization for permissible uses.
Statewide parcel rendering and township grids are heavier than thematic public-lands overlays. Turn them on when you zoom in so the map stays responsive on phones and laptops.