| Wartburg College Observatory | Waverly | — |
| Wayside Observatory | Minnetonka | — |
| Weaver Student Observatory | California | — |
| Weitkamp Observatory | Ohio | — |
| Werner Schmidt Observatory | Yarmouth | — |
| West Mountain Observatory | Utah | — |
| West Skies Observatory | Mulvane | — |
 Weston Observatory | Nuevo Hampshire | — |
 Weston Observatory | Weston | — |
 Westport Observatory | Westport | — |
| WestRock Observatory | Columbus | — |
| Westwood observatory | Westwood | — |
| Whipple observatory | Cañón de Madera | — |
| Whipple Observatory | Madera Canyon | — |
| Whiskey Creek Observatory | Silver City | — |
 Whitefish Point Bird Observatory | Míchigan | — |
 Whitin Observatory | Massachusetts | — |
 Wide Field Infrared Explorer | — | — |
 Wide-field Infrared Survey Explorer | — | — |
| Widener University Observatory | Pensilvania | — |
 Wilder Observatory | Massachusetts | — |
| Willard L. Eccles Observatory | Utah | — |
| William Miller Sperry Observatory | Nueva Jersey | — |
| Williams Observatory | Carolina del Norte | — |
| Willowed Plains Observatory | Manteno | — |
| Winchester observatory | Winchester | — |
| Winer Observatory | Sonoita | — |
| Winfree Observatory | Lynchburg | — |
| Wishing Star Observatory | Barrington | — |
 Wyoming Infrared Observatory | Condado de Albany | — |
| Wyrick Observatory | Haymarket | — |
| Yale Observatory | Bethany | — |
| Yale Student Observatory | New Haven | — |
 Yale University Observatory | Connecticut | — |
| Yellow Springs observatory | Yellow Springs | — |
 Yuba City Astronomical Observatory | California | — |
| Zeno Observatory | Edmond | — |
| Zephyrhills observatory | Zephyrhills | — |