Gyomaendrőd lies on the left (south) bank of the Hármas- (Triple-) Körös River. This stretch of the river is the most beautiful waterside landscape of the region. It’s about 100 meters wide and the water is 6 meters deep on the average. It is a region rich in fish and wild animals. The Békés County stretch of the Hármas-Körös floodplain area, which covers more than 2,000 hectares is part of the Körös-Maros National Park.