Colorado - Area of significance: Architecture
| 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 |
| 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 Post Office |
| Fort Lyon |
| Fort Morgan Power Plant Building |
| Fort Morgan State Armory |
| Fort, The |
| Fort Vasquez |
| Foster, A. C., Building |
| Foster-Buell Estate |
| Foster, Ernest LeNeve, House |
| Foster House Stage Station and Hotel Site |
| Fountain Inn |
| Four-Mile House |
| Fourth Church of Christ, Scientist |
| Fox Stone Barn |
| Francisco Plaza |
| Frantz, D. E., House |
| Frazier, R. T., House |
| Frisco-Bagley Mine and Tunnel |
| Fruita Museum |
| Fruitdale Grade School |
| Fuller, Granville, House |
| Fuller, Montezuma, House |
| Galligan House |
| Garcia-Espinosa-Garland Ranch Headquarters |
| Garnethurst |
| Gas Creek School |
| Gast Mansion |
| Gates, Russell and Elinor, Mansion |
| Gebhard Mansion |
| General Electric Building |
| Genesee Park |
| Geneva Home |
| German Evangelical Immanuel Congregational Church |
| Giddings Building |
| Gimlett/LeFevre Cabin |
| Ginacci House |
| Glacier Basin Campground Ranger Station |
| Glassier Farmstead |
| Glazier House |
| Glenarm Place Historic Residential District |
| Glen Eyrie |
| Glen Grove School |
| Glenisle |
| Golconda Mine |
| Golden Cemetery |
| Golden High School |
| Goldfield City Hall and Fire Station |
| Gold Hill Historic District |
| Gold Miner Hotel |
| Grace and St. Stephen's Episcopal Church |
| Grace Episcopal Church |
| Grace Episcopal Church |
| Grafton, The |
| Grand Lake Lodge |
| Grant-Humphreys Mansion |
| Gray, Garret and Julia, Cottage |
| Greeley High School |
| Greeley High School and Grade School |
| Greeley Junior High School |
| Greeley Masonic Temple |
| Greeley Tribune Building |
| Greeley Union Pacific Railroad Depot |
| Greenwood Lodge |
| Gregory, William J., House |
| Grimm, S. A., Block |
| Guerrieri-Decunto House |
| Guiraud-McDowell Ranch |
| Gully Homestead |
| Gwynne-Love House |
| Hagerman Mansion |
| Hallett, Samuel I., House |
| Hamburger, George, Block |
| Hammar, Benjamin, House |
| Hanigan-Canino Terrace |
| Hargreaves Homestead Rural Historic District |
| Harmony Mill |
| Harms Farm |
| Harris Park School |
| Hart, Wilson A., House |
| Haxby House |
| Hayden Ranch Headquarters |
| Hayden Rooming House |
| Haynie Site |
| Hazelhurst |
Data from United States Park Service and Wikidata
