Question

What is the significance of The Significance of the Frontier in American History on American history?

Answer 1

"In 1893, three years after the superintendent of the Census announced that the western frontier was closed, Frederick Jackson Turner, a historian from the University of Wisconsin, advanced a thesis that the conquest of the western frontier had given American society its special character. At the Columbian Exposition in Chicago, marking the 400th anniversary of Columbus's discovery of the New World, Turner argued that the conquest of the western frontier as the (American) nation's formative experience, which had shaped the nation's character and values. Western expansion accounted for Americans' optimism, their rugged independence, and their stress on adaptability, ingenuity, and self reliance.

In actuality, however, the settlement of the West had depended, to a surprising degree, on intervention by the federal government. The federal government had dispatched explorers to survey the region and cavalry units to confine Native Americans on reservations. It also provided land grants that funded railroad building, and, in the 20th century, support for dams and other waterworks.
In his address on the significance of the frontier in American history, Turner referred to the Census Bureau's announcement that the frontier was now closed. He speculated that now that the frontier was settled, a crucial epoch in American history was over. "

I can't do better than this, though it's important to note that it is only a thesis, a theory concerning the evolution of American uniqueness as a nation. Simon Schama has written about landscape and frontier in his work more recently, and Fernand Braudel often said that geography was the most important of the social-sciences.

Regarding 'frontiers', there are always frontiers to be explored. They can be scientific, geographic, political, or economic, the challenges facing a society are ever changing. Following 1893, the US expanded it's sphere of influence into the former Spanish Empire to the south, in Central and South America, fighting against Spain, Mexico, and Cuba, eventually obtaining territories which expanded it's influence. In 1969 John F Kennedy made it clear that the US considered space to be a frontier, with the development of the US Space program, the launching of satellites into orbit, and the Moon landings. In a sense Turner's thesis is tested every time a US probe lands on a distant planet. At present Mars features on the horizon, as the next challenge, as the next frontier.