Mount Barnard is a mountain in the U.S. state of California, and has the dubious distinction of being the highest thirteener, a peak between 13000 and 13999 ft in elevation, in the United States. It is located on the Sierra Crest and straddles the boundary between Tulare and Inyo counties about 2 mi southwest of Mount Williamson, the second-highest peak in the state; Mount Barnard is the twelfth-highest. The first ascent was by W. L. Hunter, John Hunter, William Hunter and C. Mulholland on September 25, 1892. They named the peak in honor of E. E. Barnard, a noted astronomer.