The Łomnica River begins at an elevation of 1,407 m above sea level. Its source areas are Wielki Staw and Mały Staw. The Łomnica is characterized by a dramatic water drop (especially in its upper reaches), where the elevation difference is 927 meters (source 1,407 m above sea level, mouth 480 m above sea level). In the town of Łomnica, the river flows into the Bóbr River, forming its left tributary. The Łomnica's drainage basin covers an area of approximately 118 km² and is approximately 19 km long.