Abstract The Mount Diablo meridian is named for the location of its initial point on Mount Diablo in California. The meridian extends to the north and south from Mount Diablo and is used to describe lands in most of northern California. Along this meridian is a fractional township area encompassing land in northern California adjacent to the Oregon-California border. Collection consists of a copy of a map of January 6, 1873, made in 1907. The area mapped is directly to the South from the...