There are a number of historical perspectives and events that justify the Great Plains as the end of the Midwest and the beginning of the American West. The most noticeable differences begin at approximately the 100th meridian as changes with climatic conditions, vegetation, and animal life become more readily apparent. In addition, historical events, such as the last major United States-Indian confrontation at Wounded Knee and the non-Indian settlement of the Northern Great Plains in the late nineteenth century, coincided with the proclaimed end of the frontier experience in United States history.
"Where The Midwest Ends and The Great Plains Begin,"
Studies in Midwestern History: Vol. 1
, No. 6.
Available at: https://scholarworks.gvsu.edu/midwesternhistory/vol1/iss1/6