Ontario Motor Speedway was a motorsports complex in Ontario, California, United States. The complex featured various layouts, including a 2.500 mi (4.023 km) rectangular oval and a 3.194 mi (5.140 km) roval road course. From its opening in 1970 until its closure in 1980, the facility hosted numerous major racing events, including USAC, CART, NASCAR, IMSA GT Championship, NHRA, and exhibition Formula One events. The track since its closure has been demolished, with the track site now occupied by the Ontario Center, a mixed-use commercial center, which includes shopping centers, housing developments, hotels, a school, office space, a public park, and the Toyota Arena.