Kitt Peak National Observatory
Supports the most diverse collection of astronomical observatories on Earth.

Royal Greenwich Observatory British Government.
Founded in 1675 by Charles II. The site includes history, astronomical research, and particle physics research.

Apache Point Observatory
Located in the Sacramento Mountains of south central New Mexico.

Golendale Observatory
Near Goldendale, WA. Owned by Washington State and run by the parks dept. It has a 24.5 inch scope.

National Optical Astronomy Observatories Association of Universities for Research in Astronomy (AURA).
A major site for University research, lots of projects. Also, a K-12 outreach program.

Rattlesnake Mountain Observatory
The facility is located in Southeast Washington between Yakima and the Tri-City area. It has a 31" instrument fitted for remote operation.

Steward Observatory University of Arizona
The research division of the University Astronomy Department. One of the premier astronomy research facilities in the world - observational and theoretical. Includes lots of related links such as the famous UofA mirror Lab.

Mount Wilson Observatory
The famous facility near Pasadena, CA. Founded in 1904 by George Ellery Hale.