3 Days at the Fair is a fixed-time ultrarunning series held in May at the Sussex County Fairgrounds in Augusta, New Jersey. Runners can choose from 6, 12, 24, 48, 72, or 144 hours, with separate day and night options for the shorter races. Marathon and 50K races are also offered on multiple days, and the Quadzilla challenge requires finishing four marathons or four 50Ks during the event.
The course is a flat, certified 1.000-mile loop on pavement and crushed gravel, with gravel comprising about 5 percent of each lap. The marathon course is certified as a Boston Qualifier, and the 50K is certified as well, making lap counting important alongside endurance. The loop is lit at night, runners can view a live display for laps and position, and the fairgrounds provide a practical setting with heated bathrooms, showers, a full kitchen at the aid station, space for tents, RV parking, and electrical outlets near camping areas. Phil McCarthy set an American record at this race, which suits its design for participants who aim to keep moving, rest as needed, and then resume for another exact mile.