California Code, Government Code - GOV § 23126

The boundaries of Mono County are as follows:

Beginning at the north corner on the state line, being the east corner of Alpine; thence southwesterly, on the easterly line of Alpine to the main summit of the Sierra Nevada Mountains; thence southerly, along said summit, on the easterly line of Alpine, Tuolumne, Madera, and Fresno, to a point where the northern line of T. 6 S., M.D.B., intersects said summit line, forming the southwest corner; thence east, on said township line, being the northern line of Inyo, to the eastern line of the State, forming the southeast corner; thence northwest, on the state line, to the place of beginning.