State Route 115 is a state highway in the U.S. state of California. It runs in Imperial County from Interstate 8 (I-8) southeast of Holtville to SR 111 in Calipatria. The routing was added to the state highway system in 1933, and was constructed by 1934; SR 115 was officially designated in the 1964 state highway renumbering.

There are 34 routes assigned to the "S" zone of the California Route Marker Program, which designates county routes in California. The "S" zone includes county highways in Imperial, Orange, Riverside, San Diego, and Santa Barbara counties.