The Frontier Thesis, also referred to as the Turner Thesis, is the argument advanced by historian Frederick Jackson Turner

Frederick Jackson Turner

Frederick Jackson Turner was an American historian in the early 20th century. He is best known for his essay "The Significance of the Frontier in American History", whose ideas are referred to as the Frontier Thesis. He is also known for his theories of geographical sectionalism...

 in 1893 that the origin of the distinctive egalitarian, democratic, aggressive, and innovative features of the American character has been the American frontier experience. He stressed the process—the moving frontier line—and the impact it had on pioneers going through the process.