The Supermaraton Królewski is a forest ultramarathon held in Gołąbki, near Trzemeszno, within the Gołąbki Forest District. It takes place in mid-August on a 25 km cross-country loop. The main race covers 100 km across four laps, with options for 75 km or 50 km. A four-person relay is also available. Fundacja Aktywne Trzemeszno organizes the event, supported by Powiat Gnieźnieński and Nadleśnictwo Gołąbki. The setup provides food support, medical care, and electronic timing.
The course involves running the same forest loop multiple times, making pacing and loop management as important as speed. The race originated from the Festival Słońca, where the 100 km was the primary event, complemented by shorter distances like 50 km, 25 km, and 10 km to accommodate more participants. Stowarzyszenie Sportowe Polskie Ultra has backed the event, bringing many runners across all distances. A previous 100 km race was won in 7:14:52, a time noted as competitive for road races, while the women's top finishers were closely grouped around ten hours.