The Pomme de Terre River begins cool and clear in Otter Tail County, bordered by wooded hills and grassy meadows. It flows south through several lakes; as the river nears its mouth, it is bordered by eroding banks, becoming increasingly muddy before discharging into the Minnesota River at Marsh Lake. The Pomme de Terre watershed is located in parts of Otter Tail, Grant, Douglas, Stevens, Big Stone, and Swift counties.
Land use within the watershed is primarily agricultural, accounting for approximately 81% of the available acres. There are impairments starting from Barrett Lake and continue to the outlet to the Minnesota River at Marsh Lake.