Eggedal is located between Numedalsfjellene in the west and Norefjell in the east, stretching northwards from the mountain Andersnatten, and borders in the north to Flå in Hallingdal. Eggedal is situated to the west of the Norefjell mountain range. There is farmland on the valley floor. In all other directions, the terrain rises quite steeply. The sprawling valley of Eggedal was formed by the meandering Eggedøla River. It begins as the Haglebu river a few miles north of Lake Haglebuvatna with top sources in the regions bordering Nes and Nore og Uvdal. As it passes through Eggedal, the river is known as the Eggedøla until it reaches Lake Soneren. As it exits the lake, the name is changed to the Simoa river.