The southern boundary is the southeastern corner of Glacial Lake Agassiz. To the east, the boundary is the Vermillion River up to the point it turns to the east and enters Crane Lake. This boundary marks the division between bedrock controlled uplands with shallow soils and glacial lake plain with bedrock knobs present but not dominant. This is a level to gently rolling lakeplain and transition zone to the Border Lakes region to the east.
Soils are clayey to loamy and formed from lake laid sediments and glacial till.
Topographic relief is less than 50 ft on most of the lake plain, becoming greater to the east in the transition zone. This subsection is transitional between extensive peatlands to the west and bedrock controlled landscape to the east. The major landform on the west side is lake plain. On the east side, the glacial lake had a very irregular shoreline. It squeezed between bedrock outcrops, depositing sediments like fillings in teeth.