The 1973 Northern 300 at Trenton Speedway was scheduled for July 15 but never ran.
Qualifying on July 14 saw Bobby Allison take the pole in his Chevrolet at 131.707 mph, with Richard Petty second, Cale Yarborough third, and Buddy Baker fourth for a planned 30-car field.
Heavy rain washed out race day. Officials postponed it to August 5, but the promoter cancelled it on July 27, citing too little time to properly promote the rescheduled event. It marked the end of NASCAR’s visits to Trenton.