Congress admitted Illinois as the 21st state of the United States, following the pattern of territorial expansion that reshaped the young republic's map in the early nineteenth century. With a population of barely 40,000 at the time, mostly clustered along the Mississippi and Ohio rivers, Illinois would go on to become one of the most consequential states in American history, producing Abraham Lincoln and eventually the city of Chicago.
When Illinois achieved statehood, its population was concentrated almost entirely in the southern part of the territory, near the confluence of the Mississippi and Ohio Rivers; the site of future Chicago was then a small trading outpost. Statehood required a minimum population threshold, and Illinois's territorial legislature reportedly inflated its census figures to meet the requirement, a common practice among frontier territories eager for full political representation.
The first state constitution, drafted in a hurried convention in Kaskaskia, tellingly restricted voting rights and grappled uneasily with the question of slavery even as it nominally banned it, permitting existing indentured servitude arrangements to continue. Within decades, canal and railroad construction linking the Great Lakes to the Mississippi watershed would transform the state's fortunes entirely, turning Chicago from a swampy outpost into America's great inland metropolis and Illinois into a bellwether of national political life.