The El Toro "Y" is a freeway interchange in southern Orange County, California where the Santa Ana Freeway, Interstate 5 (I-5), and the San Diego Freeway (at that point the I-405) merge. South of the El Toro Y, the highway is named the "San Diego Freeway" with the highway designation "I-5." Located in south Orange County where the cities of Lake Forest, Laguna Hills, and Irvine converge, the interchange was named after the nearby city (El Toro - now Lake Forest) and the now-closed Marine Corps Air Station El Toro, located northeast of the interchange.