It is evident that the front line of people will always be at right angles to the direction of movement, representing, as it does, the fore most wave of advance. This is the "frontier." Technically it is the long, narrow, advanced strip which contains more than two people and less than six people to the square mile. The latest aspect of the frontier is associated with the Great Plains and cowboys; but the frontier in past times has occupied successive positions from the Alleghanies westward at each suc ceeding census. Its various positions remind one of the old sea beaches on a geological map. When young Andrew Jackson migrated to Tennessee and lodged in the "lean-to° of Mrs. Donelson, built against her to cabin, he was on the frontier of that day. When Abraham Lincoln's mother died 18 miles from a physician in a southern Indiana cabin, it marked the hardships of the frontier. When "border ruf fians" contested with "Thayerites" for the pos session of eastern Kansas, the frontier had reached that point.
Manifestly, if the start had been equal all along the line and the rate of progress equal, the frontier line would have been almost a straight line. But the topography of the land and the hostility of the Indians prevented such a regular advance. Long arms of people ran up the streams, islands of people were formed far in advance and deep indentations frequently resulted from some hindrance. The frontier of 1830, for example, extended in a great convex westwardly curve from Detroit, Mich., to New Orleans. It threw out so many projections along the Wabash, the Illinois, the Mississippi, the Missouri, Arkansas and Red rivers that it was 5,300 miles long. Ten years later it had filled out these inequalities so much that al though it extended from Green Bay, Wis., to Corpus Christi, Tex., it was only 3,300 miles in length.
No prediction could be safely made as to direction or rate of motion. A rush or "boom" would make a fully populated region out of what was yesterday an untenanted wilderness. The census of 1830 showed a barren sweep about the head of Lake Michigan with less than two white men to the square mile except in the lead mines in northern Illinois and a group about Kalamazoo, in southern Michigan. Ten years later the lake was skirted from north of Milwaukee far down into Indiana by from 6 to 18 people to the square mile. Within the decade, it had leaped through the intermediary stage of the frontier. In 1830 Mississippi was settled only in a narrow strip across the south ern part. Ten years later the entire State,
except a spot near the Gulf, was covered with a population in many places of 20 people to the square mile.
The frontier in 1860 lay almost due north and south just west of Iowa and Missouri. It was the line-up for the final dash across the Great Plains, the best known and most pictur esque of all the positions of the frontier. In 1890 it had assumed its highest achievement and was in its proudest position. Beginning at the Canadian border near longitude 100 it came down through the Dakotas and suddenly turned westwardly, encompassing the larger part of Colorado, and rounding down into Texas on the south. But 10 years later, popu lation had so shrunken in the "dry farming" districts of Nebraska, Kansas and Colorado, that the line had fallen back, almost coincident with the meridian of 101° west longitude from the Canadian boundary' to the Rio Grande. For the first time in its history, the American frontier had retreated. Nature, driven hack step by step through the conquering will and forces of men, seemed to have taken her stand in the arid regions and to defy further encroach ments upon her realm. National irrigation under the form of internal improvement is now the weapon with which she will again be overcome.
The movement of population, which con quered the continent and unified the American people, was not only a westward movement but a due west movement. Men follow parallels of latitude because of similarity of climate, occu pation, products, foods and dress. The con stant tendency to migrate due west is shown in a study of Americans living in one State who were born in another. New York, to illustrate, has contributed more citizens to New Jersey than to any other State; then to Michigan, Pennsylvania and Illinois in decreasing order, but all to the westward. Georgia has sent more of her citizens to Alabama than to any other State; then to Texas, Florida, Tennessee, Arkansas and Mississippi, in decreasing ratio. Arkansas and Iowa are about equally distant from the Atlantic, the place of setting out. But in the onward march, 26 New Yorkers found their way to Iowa for every one to Arkansas. On the other hand 57 South Carolinians have chosen to live in Arkansas for every one who chose to remove to Iowa. The State of Wash ington has drawn most largely upon Illinois and Texas most heavily upon Tennessee. All this had a most important bearing on Northern and Southern sectionalism.