Stock car races in the then-NASCAR Winston Cup Series have been held at the Riverside International Raceway in Riverside, California during numerous times of year and season from 1958 to 1988.
The Winston Western 500 was an annual NASCAR Winston Cup race held at Riverside International Raceway in Riverside, California, United States, in January, and then in later years, November. From 1963 to 1981, the race was held in January and was the season opening race. NASCAR elected to start its season with the Daytona 500 beginning in 1982, so a second Winston Western 500 was run in November to accommodate the change; the change resulted in Riverside hosting three Winston Cup races in 1981. The race ran in November from 1981 to 1987, serving as the Winston Cup Series' final race of the year from 1981 to 1986. The race distance was 500 miles until 1977 when it was shortened to 311 miles (500 kilometers). The other race held at Riverside, the Budweiser 400, was held in June.
The Budweiser 400 was an annual summer NASCAR Winston Cup race held from 1970 to 1988 at Riverside International Raceway in Riverside, California, United States. A 400-mile race was also run at the track in November 1963. The race distance was 400 miles until 1976 when it was shortened to 249 miles (400 kilometers). The other race at Riverside, the Winston Western 500, was held in January from 1965 to 1981 and November from 1981 to 1987.