The United States Road Racing Championship was a racing series sanctioned by the Sports Car Club of America from 1963 to 1968. It featured racing prototypes and production grand touring cars. It was replaced by the Trans Am Series and Can Am Series spinoffs, including the use of an over two liter group and an under two liter group. The series was revived in 1998, reviving the Can Am name for its prototypes, but with no relation otherwise to the classic series. This revival was shortlived, and the series was quickly purchased by NASCAR and reorganized into the Grand American Road Racing Association's Rolex Sports Car Series. However, the revived USRRC did receive the Six Hours of Watkins Glen and the 24 Hours of Daytona from the IMSA GT Championship for odd reasons.
The Monterey Historic Automobile Races at Mazda Raceway Laguna Seca recently added USRRC cars in an attempted remix of its prototype groups, initially substituting them for its Can Am race group. For this year the cars are being mixed with the Can Am cars as they are essentially the direct ancestor of Can Am.