Magdalena Ridge Observatory, Astronomical observatory in Magdalena Mountains, Socorro County, US.

Magdalena Ridge Observatory is an astronomical research facility located in the Magdalena Mountains at an elevation of about 3,230 meters (10,600 feet). The site houses multiple telescopes and an optical interferometer used to study stars and distant cosmic objects.

The interferometer's basic design was completed in 2006, and construction began that August with the Beam Combining Facility, finished in 2008. The first of ten planned 1.4-meter telescopes was installed in 2016; work paused in 2019 when AFRL funding was withdrawn, then resumed in 2021. By 2025 a second telescope and two beamlines were in place.

The site is run by New Mexico Tech in Socorro, which partners with the University of Cambridge's Cavendish Astrophysics Group on the interferometer. The Air Force Research Laboratory funds the array, and the University of Minnesota manages a set of robotic telescopes there. New Mexico State University, New Mexico Highlands University, the University of Puerto Rico and Los Alamos National Laboratory were early partners but withdrew.

Access to the facility is limited and primarily serves research purposes. Those interested in visiting should inquire in advance with the operating institution about whether tours are available.

The 2.4-meter telescope's main mirror was made by Itek for a bid to build the Hubble mirror; when Perkin-Elmer won the contract, it went to a classified Air Force project and later came here with a spare secondary blank. The interferometer's ten 1.4-meter telescopes will sit on three 340-meter arms, moved by a custom crane.