Colorado - Role: Building
| Loveland State Amory |
| Lowry Field Brick Barracks |
| Luft, Conrad, Sr., House |
| Lyons Railroad Depot |
| Macedonia Baptist Church |
| Machebeuf Hall |
| Maitland Estate |
| Mancos High School |
| Mancos Opera House |
| Manhattan Hotel |
| Manitou Bathhouse |
| Manzanola United Methodist Church (MUMC) |
| Marble City State Bank Building |
| Marble High School |
| Marble Jailhouse |
| Marble Town Hall |
| Margery Building |
| Masonic Temple Building |
| Mathews House |
| Maxwell Building |
| Maxwell Park School |
| Maxwell, R. G., House |
| Maysville School |
| Maytag Aircraft Building |
| McAllister House |
| McClelland Orphanage |
| McClellan House |
| McClintock Building |
| McClure House |
| McCormick House |
| McCourt, Peter, House |
| McCreery, William H., House |
| McFadden Barn |
| McGregor Hall |
| McHugh-Andrews House |
| McPhee and McGinnity Building |
| McPhee and McGinnity Paint Factory |
| Mechanics Building/Masonic Building |
| Meeker I.O.O.F. Lodge-Valentine Lodge No. 47 |
| Meeker Memorial Museum |
| Melvin School |
| Mesa Schoolhouse |
| Methodist Episcopal Church |
| Methodist Episcopal Church of Montrose |
| Midland Savings Building |
| Midland Terminal Railroad Depot |
| Midland Terminal Railroad Roundhouse |
| Midwest Steel and Iron Works Company Complex |
| Mill City House |
| Miller House |
| Mills, Enos, Homestead Cabin |
| Milner Pass Road Camp Mess Hall and House |
| Milner-Schwarz House |
| Minnequa Steel Works Office Building and Dispensary, Colorado Fuel and Iron Company |
| Mint Saloon |
| Miramont |
| Missouri Heights School |
| Modoc Mill |
| Moffat Station |
| Monte Vista Library |
| Montezuma Schoolhouse |
| Montezuma Valley National Bank and Store Building |
| Montgomery Court |
| Montgomery Hall, Colorado College |
| Montgomery Ward Building |
| Montrose City Hall |
| Montrose County Courthouse |
| Montrose Fruit & Produce Association Building |
| Montrose Masonic Temple, Lodge No. 63 |
| Montview Boulevard Presbyterian Church |
| Moore, Dora, Elementary School |
| Moraine Lodge |
| Morgan County Courthouse and Jail |
| Morrison Schoolhouse |
| Mosman House |
| Mosque of the El Jebel Shrine |
| Motor Coach Division Building-Denver Tramway Company |
| Mountainside Lodge |
| Mount Saint Scholastica Academy, East Building |
| Mount Vernon House |
| Mt. Pleasant School |
| National Fuel Company Store |
| National Hotel-Wolff Building |
| Navajo Hogan |
| Neef, Frederick W., House |
| Nettleton-Mead House |
| Neusteter Building |
| Newberry House |
| New Brick-The Brick Saloon |
| Newman Block |
| New Terrace |
| Niblock-Yacovetta Terrace |
| Nichols House |
| Nordlund House |
| Norman Apartments |
| Northern Colorado Power Company Substation |
| North La Junta School |
| Notch Mountain Shelter |
| Nunns, John Herbert, House |
| Nurses' Home |
Data from United States Park Service and Wikidata
