Population of 1818.—The table on page 142 shows how sparsely populated the state was at the time of its admission to the Union.
The table includes only the white population of that part of the state which had been surveyed. Crawford, Bond, and Madison counties included small areas of surveyed lands in their southern borders, and about 43,000 square miles additional, consisting of the recently surveyed lands of the "military tract" and the unsurveyed lands of the state. The returns of the census of 1818 showed a population beyond the line of survey sufficient to bring the total for the state to 40,000, which was the number required for statehood by the terms of the Enabling Act. Thus at the time of admission to the Union, Illinois had a population density of but 3 per square mile in the region open to settlement, and less than 1 per square mile for the state as a whole. Only a region of remark able promise could have attracted a population of 6,000,000 in a single century.
The distribution of this early population was determined largely by natural conditions. The waterways were the easiest routes of travel. Timber for buildings and for fuel and water for domestic use were easily obtained near the streams. Game abounded in the forest, and agriculture was readily developed on the small prairies or cleared forest land. A population of about 15,000 was found in an area of 2,000 square miles between the Mississippi River on the west and Kaskaskia River and Shoal Creek on the east. Along the Wabash River from the Indiana state line to Saline River in Gallatin County, in a strip of territory about 15 miles wide and more than 100 miles in length, lived a population of 12,000 on an area of 1,500 square miles. These two centers of population had a density of about S per square mile. Only 17,000 inhabitants were found in the remaining S,000 square miles of surveyed lands, a density of less than 2 per square mile.
Professor Buck has traced the birthplace or former residence of 716 heads of families who resided in Illinois when the census of ISIS was taken (Table II). These are about 12 per cent of the 6,020 families then living in Illinois. The summary includes birthplace, or the earliest known residence if the birthplace could not be determined from the records. Another classifica
tion is shown in Table III: Since the population had nearly all moved into the state after 1800, the attractions of the Illinois country must have been widely known to have drawn, in so short a period, a popu lation whose former homes had been in 1S other states and 6 foreign countries.
Settlement of central and northern Illinois.—When Illinois was admitted to the Union, Indian claims had been extin guished for less than half the state. These lands lay in two detached areas, one in the southern third of the state and the other to the north and west of the Illinois River. Indian claims overlapped in many cases and the same territory was involved in more than one Indian treaty. The Piankashaw had ceded the last of their claims in Illinois in 1805, the Sac and Fox in 1815, and the Illinois in 1S1S. These cessions had been completed before Illinois was admitted as a state. The Kickapoo made final cession of Illinois land in 1819, the Winnebago in 1829, and the I'otawatomi in 1833.
After government ownership had been established, the regions of the state were rapidly surveyed into townships, sections, and quarter-sections, and opened to entry. The frontier line of settlement moved steadily northward, more rapidly along the streams and forested belts than in the prairie regions. This movement of an incoming population is well described in the Geography of the Middle Illinois Valley: In 1820 population was confined to the southern portion of the state. During the next few years settlement spread northward into the Sangamon region. In 1823. Springfield was a frontier village containing a dozen log cabins; the site of Peoria was occupied by a few families, and that of Chicago by a military and trading post. The rest of northern Illinois was entirely unoccupied. In the latter part of the twenties, the Sangamon count ry filled rapidly, one hundred wagons in a single train being fre quently seen on their way there. A new impetus was given to the movements by the establishment of stream navigation on the Illinois River in 1828. By 1830 the Sangamon district was over lowing into the Illinois Val ley, which contained a few settlers well beyond Peoria.