Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observatory is granted to Caltech and its research partners, which include the Jet Propulsion Laboratory (JPL), Yale University, and the National Astronomical Observatories of China.

Palomar Mountain is a mountain ridge in the Peninsular Ranges in northern San Diego County. It is famous as the location of the Palomar Observatory and Hale Telescope, and known for the Palomar Mountain State Park.