Colorado - Criteria: C (architecture/engineering)
| Colorado Sanitary Canning Factory |
| Colorado Springs Airport |
| Colorado Springs and Cripple Creek District Railway-Corley Mountain Highway |
| Colorado Springs City Auditorium |
| Colorado Springs City Hall |
| Colorado Springs Day Nursery |
| Colorado Springs Fine Arts Center |
| Colorado Springs Public Library-Carnegie Building |
| Colorado State Capitol Annex Building and Boiler Plant |
| Colorado Ute Power Plant |
| Colorado Women's Prison |
| Columbia Cemetery |
| Columbine |
| Commandant of Cadets Building, US Air Force Academy |
| Commercial Hotel |
| Como Cemetery |
| Como Roundhouse, Railroad Depot and Hotel Complex |
| Como School |
| Conifer Junction Schoolhouse |
| Coors, Herman, House |
| Corazon de Trinidad |
| Corbin, E.W., House |
| Cornwall Apartments |
| Cortez High School |
| Cossitt, Frederick H., Memorial Hall |
| Costilla Crossing Bridge |
| Cottonwood Creek Bridge |
| Cozens Ranch House |
| Cranmer House |
| Cranmer Park |
| Crawford Hill Mansion |
| Crawford House |
| Crested Butte Denver and Rio Grande Railroad Depot |
| Creswell Mansion |
| Crissey, Herbert and Edith, House |
| Crocker, F. W., and Company Steam Cracker Factory |
| Croke-Patterson-Campbell Mansion |
| Cross Land and Fruit Company Orchards and Ranch |
| Crow-Hightower House |
| Crowley School |
| Crown Hill Burial Park |
| Crystal Valley Cemetery |
| Curry-Chucovich House |
| Curtis-Champa Streets District |
| Curtis Hardware Store |
| Cutler Hall |
| Daniels and Fisher Tower |
| Daniels School |
| Davies' Chuck Wagon Diner |
| Davies Hotel |
| Deaton Sculptured House |
| Debs School |
| Dedisse Park |
| DeGraff Building |
| DeLaney Barn |
| Delta County Bank Building |
| Denver and Rio Grande Depot |
| Denver and Rio Grande Railroad Locomotive No.169 |
| Denver and Rio Grande Western Railroad Depot |
| Denver and Rio Grande Western Railroad Locomotive No. 315 |
| Denver Athletic Club |
| Denver City Cable Railway Building |
| Denver City Railway Company Building |
| Denver Civic Center Classroom Building |
| Denver Elevator-Grain Elevator |
| Denver Mint |
| Denver Orphans' Home |
| Denver Press Club |
| Denver Public Library |
| Denver & Rio Grande Railroad Box Outfit Car No. 04414 |
| Denver & Rio Grande Railroad San Juan Extension |
| Denver & Rio Grande Railroad South Fork Water Tank |
| Denver & Rio Grande Western Railroad Caboose No. 0577 |
| Denver & Rio Grande Western Railroad Locomotive No. 278 and Tender |
| Denver & Rio Grande Western Railroad Stock Car No. 5620 |
| Denver & Rio Grande Western Railroad Stock Car No. 5679D |
| Denver Tramway Powerhouse |
| Deputy Warden's House |
| Devils Kitchen Picnic Shelter |
| Dexter Cabin |
| Dey Building |
| Dickens Opera House |
| Dickinson Branch Library |
| Dixon-Markle House |
| Dodge-Hamlin House |
| Dolores River Bridge |
| Douglas Crossing Bridge |
| Downtown Boulder Historic District |
| Downtown Denver Central YMCA and Annex |
| Dow-Rosenzweig House |
| Doyle-Benton House |
| Doyle Settlement |
| Drennan School |
| D & RG Narrow Gauge Trestle |
| Duke, Nathaniel W., House |
| Dumont School |
| Dunning-Benedict House |
| Dunwoody, William J., House |
| Durango High School |
| Durango-Silverton Narrow-Gauge Railroad |
Data from United States Park Service and Wikidata
