Ultramaraton Nadbużański in 2020, a running event organized in Mielnik (Poland) on 19 September. During the 3 races were held event. Szmergiel (⨦ 65.5 km / + 500 m) in class RMT4 with average terrain slope 1% (G1). Chazior (⨦ 35.5 km / + 500 m) in class RMT2 with average terrain slope 1% (G1). Szprut (⨦ 19 km / + 300 m) in class RMT1 with average terrain slope 2% (G2).