An oak savanna plant community located in the Upper Midwest region of the United States, it is an ecotone (a transitional area) between the tallgrass prairies to the west and the temperate deciduous forests to the east.

A part of the Upper Mississippi River basin, it is considered endangered with less than 5% of the original ecosystem remaining intact, due mostly to overgrazing and conversion to agriculture.

[3] After European American settlement and the abandonment of fire as a land management regime, most savannas have been converted into closed canopy woodlands, with shade tolerant and fire-intolerant species dominating rather than the historic primary and secondary succession species dependent on fire.

[4] Trees: A survey in 1985 concluded that only 26 square kilometres (10 sq mi) of oak savanna remain, roughly 0.02% of what is estimated to have existed at the time of European settlement.

Highly dispersed and fragmented, none of the present habitat falls under the designation of National Forests but comes under the administration of the states' Department of Natural Resources organizations or federal entities such as the Fish and Wildlife Service.