Big Woods refers to a type of temperate hardwood forest ecoregion found in western Wisconsin and south-central Minnesota.

Native vegetation based on soils information (note the bright green color) from the Natural Resources Conservation Service of the United States Department of Agriculture shows the historic extent of oak savannas in the Big Woods region (See accompanying pie chart, below).

The soil of the Big Woods is thick glacial till of crushed limestone, deposited by the Des Moines lobe of the Wisconsin glaciation 10,000 years ago.

These hills and lakes suppressed fires that were instrumental forces on the prairie to the west and the oak savanna to the south and east.

[3] Little House in the Big Woods by American author Laura Ingalls Wilder takes place near her home town of Pepin, Wisconsin.