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.

Interstate 8 (I-8) is an Interstate Highway in the southwestern United States. It runs from the southern edge of Mission Bay at Sunset Cliffs Boulevard in San Diego, California, almost at the Pacific Ocean, to the junction with I-10, just southeast of Casa Grande, Arizona. In California, the freeway travels through the San Diego metropolitan area as the Ocean Beach Freeway and the Mission Valley Freeway before traversing the Cuyamaca Mountains and providing access through the Imperial Valley, including the city of El Centro. Crossing the Colorado River into Arizona, I-8 continues through the city of Yuma across the Sonoran Desert to Casa Grande, in between the cities of Phoenix and Tucson.