Geographically the Middle West is almost conterminous with the Provinces of the Lake and Prairie Plains; but the larger share of Kansas and Nebraska, and the western part of the two Dakotas belong to the Great Plains; the Ozark Mountains occupy a portion of Missouri, and the southern parts of Ohio and Indiana merge into the Alleghany Plateau. The relation of the Provinces of the Lake and Prairie Plains to the rest of the United States is an important element in the significance of the Middle West. On the north lies the similar region of Canada: the Great Lakes are in the center of the whole eastern and more thickly settled half of North America, and they bind the Canadian and Middle Western people together. On the south, the provinces meet the apex of that of the Gulf Plains, and the Mississippi unites them. To the west, they merge gradually into the Great Plains; the Missouri and its tributaries and the Pacific railroads make for them a bond of union; another rather effective bond is the interdependence of the cattle of the plains and the corn of the prairies. To the east, the province meets the Alleghany and New England Plateaus, and is connected with them by the upper Ohio and by the line of the Erie Canal. Here the interaction of industrial life and the historical facts of settlement have produced a close relationship. The intimate connection between the larger part of the North Central and the North Atlantic divisions of the United States will impress any one who examines the industrial and social maps of the census atlas. By reason of these interprovincial relationships, the Middle West is the mediator between Canada and the United States, and between the concentrated wealth and manufactures of the North Atlantic States and the sparsely settled Western mining, cattle-raising, and agricultural States. It has a connection with the South that was once still closer, and is likely before long to reassert itself with new power. Within the limits of the United States, therefore, we have problems of interprovincial trade and commerce similar to those that exist between the nations of the Old World.