The southernmost of all midwestern states, Illinois also borders on Lake Michigan. Laced with navigable rivers and relatively short portages, Illinois provided relatively easy passage from the Great Lakes to the Mississippi River basin. Bounded by the Mississippi River to the west and the Wabash and Ohio Rivers to the east and south and situated opposite the mouth of the Missouri River, Illinois benefits from navigable rivers that link it directly to Pennsylvania, other midwestern states, states west of the Mississippi River, and the Gulf of Mexico. The Erie Canal, completed in 1825, the Illinois and Michigan Canal, completed in 1848, and other canals and river improvements greatly augmented water transportation to and from and within Illinois.
Illinois is located in the prevailing westerlies belt and in warm months the Gulf of Mexico pumps huge amounts of moisture-laden winds into the Lower Midwest, generally guaranteeing adequate precipitation at critical times of the year and enabling Illinois to grow a wide variety of fruit and vegetables. Freezing winter blasts from Canada help retard soil leaching and ensure rich, black soil throughout much of the northern two-thirds of the state. In addition, the state enjoys rich alluvial soil, especially along the American Bottom, a region that stretches along the Mississippi River's eastern bank for one hundred miles south of Alton. Growing seasons lasting over half the year in the south and about half a year in the north sustain agricultural variety.
Before French voyageurs and missionaries arrived in 1673, Iroquois Indians and others attacked and disrupted Indian societies, especially in northern Illinois, and drove some Indians over the Mississippi. French explorers found Cahokia, a former residence of mound-building Indians, virtually abandoned and relatively few Indians remaining in the region altogether. Establishing their first permanent settlement at Cahokia in 1699, the French generally established mutually beneficial ties with most Indians, intermarrying, providing via trade such goods as iron objects and other desired material culture, and exchanging ideas and understandings that fostered a "middle ground" culture, one that incorporated both French and Indian ways. By 1720 the French also had introduced slavery to Illinois.
After a series of wars with Britain in which local Indians generally sided with France or stayed neutral, France lost control of all of North America in 1763. The vast region west of the Mississippi was transferred to Spain. British occupation of Illinois was slow, difficult, and light, with only a handful of British and British colonists moving to the region before the American Revolution erupted in 1775. Britain tried to placate or even win over both the French and Indian populations of Illinois and surrounding regions, but were largely successful only with Indians in northern Illinois.
Small units fighting in Illinois and north of the Ohio River brought spectacular results. In 1778 George Rogers Clark commanded about 150 Virginians; they conquered French settlements in Illinois and then subdued the British fort at Vincennes on the Wabash. Although the American grip on lands north of the Ohio was frail, it gave Americans a claim to these lands. The entry of Spain into the war complicated the conflict for the British, and Spanish attacks against British posts from St. Louis reached northeast as far as Michigan. Peace in 1783 gave the United States not just the lands immediately north of the Ohio, but lands all the way to Lake Superior, a stunning accomplishment for the young nation.
The war introduced into Illinois a stream of settlers from Virginia and other southern states, many of whom had either served in Illinois or had relatives or friends who had served there. This migration gave Illinois powerful cultural, political, and economic links to the South and encouraged some efforts to make Illinois a slave state. In most instances, the French and the southerners coexisted reasonably well among or near each other.
The Ordinance of 1785 required that public lands be surveyed before sale, producing the familiar checkerboard land pattern common throughout the Midwest and elsewhere. This orderly method of sale avoided the tangled, bitter land disputes that flared in Kentucky and other states, inhibiting sales and cloaking social and economic developments in uncertainty. The Northwest Ordinance of 1787 was even more significant. It broke historical patterns of creating colonies from conquered lands and, instead, created a steady but radical system of allowing Illinois and the other states of the Old Northwest a measure of self-government as territories and then the right to enter the Union as full states. It also banned slavery in the region, although this had little impact on the hundreds of slaveowners and their slaves living in the region.
By 1810, the year after the Territory of Illinois was formed, trickles of migration boosted Illinois's non-Indian population to about 12,300. Its Indian population probably exceeded 14,000, many of whom kept in touch with British officers in Canada and British traders and agents around the Great Lakes. The War of 1812 triggered destruction and uncertainty, causing some settlers to flee the territory, but after peace in 1815, settlement surged. Many Indians had sided with the British during the war, leaving their cultures in tatters, and a great number of native groups left the state. The federal government continued via treaties to purchase lands from Indians who had claims to possession. A large stretch of land between the Illinois and Mississippi Rivers was designated the Military Tract and was offered as reward to military veterans. Although many veterans throughout the country never settled in this tract, they sold their rights to the land and others came to settle.
In December 1818, Illinois achieved statehood. This was done with a wink and a nod, for the population of the new state was only perhaps thirty-five thousand, far below the required level. Moreover, just before statehood, astute Illinois politicians and friends pushed the northern boundary upward from the southern tip of Lake Michigan, giving Illinois the town of Chicago, the route for the Illinois and Michigan Canal, valuable lead mines at Galena, and a region that now includes fourteen of the state's 102 counties, a region in which the vast majority of Illinois's early-twenty-first-century population lives. Kaskaskia had served as territorial capital, but the capital moved to Vandalia with statehood.
Despite sluggish national economic conditions during the 1820s, the Erie Canal opened in 1825, which did much to transform Illinois. Before the Erie Canal and the advent of predictable and inexpensive Great Lakes shipping, most flour, beef, honey, hides, and other goods shipped from Illinois were shipped downstream as far as the Gulf of Mexico, upstream transportation being prohibitively expensive and time-consuming for all but the most valuable commodities. With the Erie Canal, however, farmers and others in the northern quarter of the state and along the Illinois River could transport goods a relatively short distance to Lake Michigan, across the Great Lakes and the Erie Canal, and down the Hudson River to New York and other burgeoning cities on the East Coast. This did much to reorient Illinois economic ties from a north-south axis along the Mississippi River to an east-west axis via water and later via rail. The arrival of steamboats at St. Louis in 1817 and at Chicago in 1832 accelerated this reorientation. Land sales boomed into the mid-1830s, ten federal land offices by 1834 selling and recording orderly transactions. As the last sales from Indians occurred in the 1830s and as settlement pushed northward, the need for the state's capital to be more centrally located became apparent, and in 1839 Springfield became the capital.
Chicago became the state's largest city by the late 1830s, but the need for a canal to connect the Illinois River to Lake Michigan at Chicago became increasingly apparent, and construction on the Illinois and Michigan Canal started in 1836. The great national depression that began in 1837, however, slowed work, delaying its completion until 1848,just several years before railroads would lace Illinois.
Increased immigration to the United States and improved transportation to Illinois changed the state's population. Settlers from the Middle Atlantic states and from Ohio and New England dotted the landscape in increasing numbers. Cultural differences between them and the earlier southern settlers ignited clashes and disputes, including some friction over slavery and antislavery activities. In 1823 and 1824 Governor Edward Coles helped defeat an attempt to legalize slavery in the state. Settlers from the Northeast became involved in education and reform movements, and graduates of Yale College were responsible for the founding of the state's first institution of higher education, Illinois College, in 1829. Reform movements, including antislavery efforts, brought progress, but they also sparked political strife in the 1830s and beyond.
By 1860 the Illinois population stood at 1,711,951, perhaps about forty-five times the population at the time of statehood in 1818 and ranking it the fourth-largest state in the country. Its railroad track totaled nearly 2,800 miles, second in the country.