Mount Laguna Observatory, Astronomical observatory in Laguna Mountains, California.

Mount Laguna Observatory is an astronomical facility nestled in the Laguna Mountains at 1859 meters elevation within Cleveland National Forest. The site hosts several research telescopes designed for different types of celestial observations and scientific investigations.

The observatory was established in 1968 by the San Diego State University Department of Astronomy and marked a major advancement in the region's research capabilities. This founding allowed local researchers to participate in modern astronomical studies.

The 0.52 m Reginald Buller Visitors' Telescope, built in 1950 by J.W. Fecker, Inc., was donated to SDSU by Reginald Buller and dedicated at the observatory in 1988; students use it for direct viewing and public outreach. The 0.6 m Clifford Smith telescope was built by the SDSU astronomy department and used on the main campus from 1961 to 1966 before being modified and installed here in 1971.

The facility sits roughly 75 kilometers east of San Diego and offers excellent observing conditions due to its elevation and remote location. Most nights provide relatively clear skies with minimal light pollution from distant urban areas.

In August 2021 the observatory supplied observations that refined the orbit of (594913) 'Ayló'chaxnim, the first asteroid found inside Venus's orbit, discovered in January 2020; the data allowed its numbering that September, and it was named in November 2021. The EvryScope, a 24-aperture survey telescope built with UNC, images 8,000 square degrees every two minutes.