| Hidden Valley Observatory | |
| Alt Names: | HVO |
| Namedafter: | Road on which built |
| Organization: | Black Hills Astronomical Society |
| Location: | Rapid City, South Dakota |
| Coords: | 44.1083°N -103.2975°W |
| Altitude: | 3571 (feet) |
| Obs-Time: | Public summer star party dates listed on website |
| Telescope1 Name: | Telescope |
| Telescope1 Type: | 12.5" Reflector |
| Telescope2 Name: | Mount |
| Telescope2 Type: | German Equatorial |
| Telescope3 Name: | Telescope |
| Telescope3 Type: | 12" Reflector |
| Telescope4 Name: | Mount |
| Telescope4 Type: | Dobsonian AltAz |
Hidden Valley Observatory is an astronomical observatory owned and operated by Black Hills Astronomical Society. Located just outside Rapid City, South Dakota (USA), the observatory sits on the edge of the Black Hills National Forest. The grounds include an outdoor classroom and observation field. The public is welcome on specific dates listed on the society's website.