Montana - Area of significance: Architecture
| Montana State Training School Historic District |
| Montana State University Historic District |
| Montana Territorial and State Prison |
| Montana Veterans and Pioneers Memorial Building |
| Montgomery Ward |
| Monture Guard Station |
| Moon-Randolph Ranch |
| MORNING EAGLE (carvel-planked wooden vessel) |
| Morr, Philip and Ella, House |
| Moss, Preston B., House |
| Mountain States Telephone and Telegraph Company |
| Mount Brown Fire Lookout |
| Mrs. Lydia McCaffery's Furnished Rooms |
| Neihart School |
| New Brunswick House, The |
| Newman House |
| Norby House |
| North, Austin, House |
| Northeast Entrance Station |
| North Entrance Road Historic District |
| Northern Hotel |
| Northern Montana College Girls Residence Hall |
| Northern Montana State Fairground Historic District |
| Northern Pacific Railroad Depot |
| Northern Pacific Railroad Depot-Fromberg |
| Northern Pacific Railway Depot |
| Northern Pacific-Story Mill Historic District |
| Northside Missoula Railroad Historic District |
| North Tracy Avenue Historic District |
| Norton, W. H., House |
| Norwegian Evangelical Lutheran Church and Parsonage |
| Numa Ridge Fire Lookout |
| Nyack Ranger Station Historic District |
| O'Brien, William, House |
| O'Donnell, I. D., House |
| Olive Hotel |
| Oliver Building |
| Olsen House |
| Olsson, Don E., House and Garage |
| O'Neil Lumber Company Office |
| Oregon Short Line Passenger Depot |
| Outlook Depot |
| OW Ranch |
| Palace Hotel |
| Panton House |
| Paradise School |
| Parberry Block East |
| Parmly Billings Memorial Library |
| Parrot Mine Shops Complex |
| Pass Creek School |
| Pass Creek Snowshoe Cabin |
| Pelton, Charles and Gladys, House |
| Peoples' Congregational Church |
| Peterson House |
| Peterson Place |
| Philipsburg Grade School |
| Philipsburg Historic District |
| Pine Apartments |
| Pine Butte School |
| Ping, J. J., House |
| Poker Jim Butte Fire Lookout |
| Polebridge Ranger Station Historic District |
| Polson Feed Mill |
| Pony Historic District |
| Pope, Francis and Hannah, House |
| Popham Ranch |
| Porter Flats Apartments |
| Porter Ranch Barn |
| Potomac School |
| Powder House |
| Power, C. B., Bungalow |
| Prescott, Clarence R., House |
| Prescott Commons |
| Preston House |
| Quartz Lake Patrol Cabin |
| Quaw, Thomas, House |
| Quinn's Garage |
| Rahrer, Francis, House |
| Railroad Depot |
| Rainbow Conoco |
| Ramsay Historic District |
| Randall, Harry E., House |
| Ravalli County Courthouse |
| Raymond Grain Elevators Historic District |
| Rea School |
| Recreation Hall |
| Red Lodge Brewing Company-Red Lodge Canning Company |
| Red Lodge Commercial Historic District |
| Red Lodge Communal Mausoleum |
| Reed's Fort Post Office |
| Reese Creek School |
| Regan, Thomas P., Cabin |
| Regis Grocery |
| Reid House |
| Reid-Kent House |
| Reno Apartments |
| Residential District |
| Rialto Theater |
| Ringeling House |
| Ringleberg, Cornelius, House |
Data from United States Park Service and Wikidata
