The people of early Illinois were drawn southward by the pull of natural forces: the Mississippi washes the western border on its gulf-ward course; and the chief rivers within the State have a general southerly trend.[302] But quite as important historically is the convergence of the Ohio, the Cumberland, and the Tennessee on the southern border of Illinois; for it was by these waterways that the early settlers reached the Illinois Territory from the States of Kentucky, Tennessee, Virginia, and North Carolina. The apex of the irregular, inverted triangle of Illinois, thrust down to the 37th parallel of latitude, brought the first settlers well within the sphere of Southern influence. Two slave States flanked this southern end. Nearly one-half of Illinois lay south of a direct, westward extension of Mason and Dixon's line.
In the early days, the possession by the Indians of the northern areas accentuated the southern connections of Illinois. At the same time the absence at the North of navigable waterways and passable highways between East and West, left the Ohio and its tributaries the only connecting lines of travel with the remote northern Atlantic States. Had Illinois been admitted into the Union with the boundaries first proposed, it would have been, by all those subtle influences which go to make public sentiment, a Southern State. But the extension of the northern boundary to 42° 30' gave Illinois a frontage of fifty miles on Lake Michigan, and deflected the whole political and social history of the Commonwealth. This contact with the great waterways of the North brought to the State, in the course of time, an immense share of the lake traffic and a momentous connection with the northern central and northern Atlantic States. The passing of the Indians, the opening up of the great northern prairies to occupation, and the completion of the Illinois-Michigan canal made the northern part of Illinois fallow for New England seeding. Geographically, Illinois became the connecting link in the slender chain which bound the men of the lake and prairie plains with the men of the gulf plains. The inevitable interpenetration of Northern and Southern interests in Illinois, resulting from these contacts, is the most important fact in the social and political history of the State. It bred in Illinois statesmen a disposition to compromise for the sake of political harmony and economic progress, a passionate attachment to the Union as the _sine qua non_ of State unity, and a glowing nationalism. Illinois was in short a microcosm: the larger problems of the nation existed there in miniature.