| Etscorn Observatory | Socorro | — |
| Etters observatory | Pensilvania | — |
| Evelyn L. Egan Observatory | Estero | — |
| Everstar Observatory | Olathe | — |
| Ex Nihilo Observatory | Statham | — |
| Experimental Test Site | New Mexico | — |
 Experimento de Neutrinos Subterráneo Profundo | Municipio de Winfield | — |
| Fair Oaks Ranch observatory | Texas | — |
| Fan Mountain Observatory | Virginia | — |
 Far Ultraviolet Spectroscopic Explorer | — | — |
| Fayetteville observatory | Fayetteville | — |
| Fenton Hill Observatory | New Mexico | — |
| Fenwick Observatory | Woodside | — |
 Fernbank Observatory | Georgia | — |
| Fick Observatory | Iowa | — |
| Fire in the Sky Observatory | Brainerd | — |
| Fitz-Randolph Observatory | Universidad de Princeton | — |
| Five College Radio Astronomy Observatory | Massachusetts | 306 m |
| Flint observatory | Míchigan | — |
| Flower and Cook Observatory | Filadelfia | — |
| FOAH Observatory | Magdalena | — |
 Foothill Observatory | California | — |
| Ford Observatory | Nueva York | — |
| Four Winds Observatory | Lake Leelanau | — |
| Fox Park Public Observatory | Condado de Eaton | — |
| Foxfire Village observatory | Foxfire | — |
| Frances E. Barnard Memorial Observatory | California | — |
| Francis Marion University Observatory | Carolina del Sur | — |
| Francisquito observatory | Santa Clarita | — |
| Fredericksburg Magnetic Observatory | — | — |
 Fremont Peak Observatory | California | — |
| Fresno Magnetic Observatory | — | — |
| Frontier Observatory for Research in Geothermal Energy | Milford | — |
| FRoST observatory | Flagstaff | — |
| Frosty Cold Observatory | Addison | — |
| Frosty Drew Observatory | Rhode Island | — |
 Fuertes Observatory | Ithaca | 274 m |
| Furnace Brook Observatory | Cranston | — |
 Gaithersburg Latitude Observatory | Maryland | — |
 Georgetown University Astronomical Observatory | Washington D. C. | — |
 Georgia College Observatory | Milledgeville | — |
| Gettysburg College Observatory | Pensilvania | — |
 Glen D. Riley Observatory | Illinois | — |
| Goat Mountain Astronomical Research Station | Homestead | — |
 Goldendale Observatory State Park | Washington | — |
 Goodsell Observatory | Northfield | — |
| Governor Aker Observatory | Safford | — |
 Grainger Observatory | Exeter | — |