If those of us who have been insisting on the importance of our own region are led at times by the enthusiasm of the pioneer for the inviting historical domain that opens before us to overstate the importance of our subject, we may at least plead that we have gone no farther than some of our brethren of the East; and we may take comfort in this declaration of Theodore Roosevelt: The states that have grown up around the Great Lakes and in the Valley of the Upper Mississippi, [are] the states which are destined to be the greatest, the richest, the most prosperous of all the great, rich, and prosperous commonwealths which go to make up the mightiest republic the world has ever seen. These states . . . form the heart of the country geographically, and they will soon become the heart in population and in political and social importance. . . . I should be sorry to think that before these states there loomed a future of material prosperity merely. I regard this section of the country as the heart of true American sentiment.[178:1] In studying the history of the whole Mississippi Valley, therefore, the members of this Association are studying the origins of that portion of the nation which is admitted by competent Eastern authorities to be the section potentially most influential in the future of America. They are also studying the region which has engaged the most vital activities of the whole nation; for the problems arising from the existence of the Mississippi Valley, whether of movement of population, diplomacy, politics, economic development, or social structure, have been fundamental problems in shaping the nation. It is not a narrow, not even a local, interest which determines the mission of this Association. It is nothing less than the study of the American people in the presence and under the influence of the vast spaces, the imperial resources of the great interior. The social destiny of this Valley will be the social destiny, and will mark the place in history, of the United States. In a large sense, and in the one usually given to it by geographers and historians, the Mississippi Valley includes the whole interior basin, a province which drains into nearly two thousand miles of navigable waters of the Mississippi itself, two thousand miles of the tawny flood of the Missouri, and a thousand miles of the Ohio--five thousand miles of main water highways open to the steamboat, nearly two and a half million square miles of drainage basin, a land greater than all Europe except Russia, Norway, and Sweden, a land of levels, marked by essential geographic unity, a land estimated to be able to support a population of two or three hundred millions, three times the present population of the whole nation, an empire of natural resources in which to build a noble social structure worthy to hold its place as the heart of American industrial, political and spiritual life.