Colorado - Significance region: Local
| First Congregational Church |
| First Congregational Church of Lyons |
| First Evangelical Lutheran Church |
| First Methodist Episcopal Church |
| First Methodist Episcopal Church |
| First Methodist Episcopal Church |
| First Methodist Episcopal Church |
| First Methodist Episcopal Church |
| First Methodist Episcopal Church of Delta |
| First National Bank Building |
| First National Bank Building |
| First National Bank Building |
| First National Bank Building |
| First National Bank of Douglas County |
| First National Bank of Elizabeth |
| First National Bank of Haxtun |
| First Presbyterian Church |
| First Presbyterian Church of Eckert |
| First Presbyterian Church of Golden-Unger House |
| First Presbyterian Church of Ramah |
| First Unitarian Society of Denver |
| First United Presbyterian Church |
| First United Presbyterian Church |
| Fisher, William G., House |
| Fisher-Zugelder House and Smith Cottage |
| Fitch Terrace |
| Fitzroy Place |
| Flagler Hospital |
| Flattop Mountain Trail |
| Fleming-Hanington House |
| Florence High School |
| Florissant School |
| Flower, John S., House |
| Flowers, Jacob and Elizabeth, House |
| Flower-Vaile House |
| Foidel Canyon School |
| Ford, Justina, House |
| Fort Collins Armory |
| Fort Collins Municipal Railway Birney Safety Streetcar No. 21 |
| Fort Collins Municipal Railway No. 22 |
| Fort Collins Post Office |
| Fort Morgan City Hall |
| Fort Morgan Power Plant Building |
| Fort Morgan State Armory |
| Foster, A. C., Building |
| Foster-Buell Estate |
| Foster, Ernest LeNeve, House |
| Foster House Stage Station and Hotel Site |
| Fountain Inn |
| Fourth Church of Christ, Scientist |
| Fox Mine Office |
| Fox Stone Barn |
| Francisco Plaza |
| Frantz, D. E., House |
| Frazier, R. T., House |
| Frisco-Bagley Mine and Tunnel |
| Frisco Schoolhouse |
| Frontenac and Aduddell Mine Complex |
| Fruita Bridge |
| Fruita Museum |
| Fruitdale Grade School |
| F Street Bridge |
| Fuller, Granville, House |
| Fuller, Montezuma, House |
| Galligan House |
| Garcia-Espinosa-Garland Ranch Headquarters |
| Garnethurst |
| Gas Creek School |
| Gates, Russell and Elinor, Mansion |
| Gebhard Mansion |
| Gem Lake Trail |
| General Electric Building |
| Genesee Park |
| Geneva Home |
| German Evangelical Immanuel Congregational Church |
| Gibello's Caves |
| Giddings Building |
| Gimlett/LeFevre Cabin |
| Ginacci House |
| Glassier Farmstead |
| Glazier House |
| Glenarm Place Historic Residential District |
| Glen Grove School |
| Glenisle |
| Glenwood Springs Hydroelectric Plant |
| Golconda Mine |
| Golden Burro Cafe and Lounge |
| Golden Cemetery |
| Golden High School |
| Goldfield City Hall and Fire Station |
| Gold Hill Historic District |
| Gold Miner Hotel |
| Gold Prince Mine, Mill and Aerial Tramway |
| Goodnight Barn |
| Grace and St. Stephen's Episcopal Church |
| Grace Episcopal Church |
| Grafton, The |
| Granada Bridge |
| Grant-Humphreys Mansion |
| Graves Camp Rural Historic District |
Data from United States Park Service and Wikidata
