quality:corruption, information:extraction, information:classification
Population decline

The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles of the Great Plains have fewer than 6 inhabitants per square mile (2.3/km), the density standard that Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77/km). There are more than 6,000 ghost towns in Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal to return approximately 139,000 sq mi (360,000 km) of these drier parts to native prairie land as a Buffalo Commons.