The Big Woods comprises the western side of the Minneapolis-St. Paul metropolitan area and extends northwest of St. Cloud and southwest to Mankato. Topography of the Big Woods subsection is gently to moderately rolling. Soils are loamy, with textures ranging from loam to clay loam. The Oak Savanna subsection is a gently rolling plain of loess-mantled ridges over sandstone and carbonate bedrock and till, with morainal ridges at the southwestern edge.
Soils are a mosaic of forest and grassland generated types.
The Rochester Plateau is covered by loess along the eastern side and glacial till to the west. Topography varies from level to gently rolling. The Blufflands is a plateau covered by windblown loess that has been extensively eroded along rivers and streams. This subsection is characterized by highly dissected, bedrock controlled river valleys , with elevational relief of 500-600 ft. The St. Louis Moraines subsection is on the eastern side of this unit, characterized by rolling to steep slopes.