Naval Auxiliary Landing Field (NALF) San Clemente Island, also known as Frederick Sherman Field, is a military airport located on San Clemente Island, in Los Angeles County, California, USA. It has been owned by the United States Navy since 1937, but came into its current importance during the past decade. It is the Navy's only remaining live fire range. San Clemente is the southernmost Channel Island, covering 57 square miles (150 km²).