State Route 73 (SR 73) is an approximately 17.76-mile (28.58 km) state highway in Orange County, California. The southernmost 12 miles (19.31 km) of the highway is a toll road operated by the San Joaquin Hills Transportation Corridor Agency named the San Joaquin Hills Transportation Corridor, which opened in November 1996. The northernmost 5.76 miles (9.27 km) of the highway, which opened in 1978, is part of the Corona del Mar Freeway. SR 73's southern terminus is at Interstate 5 (I-5) near the San Juan Capistrano–Mission Viejo–Laguna Niguel tripoint. Its northern terminus is at Interstate 405 (I-405) in Costa Mesa. The highway's alignment through the San Joaquin Hills follows an approximately parallel path between the Pacific Coast Highway and I-405. Currently, there are no HOV lanes for the three-mile freeway segment, but the medians have been designed with sufficient clearance for their construction should the need arise in the future.