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Illinois Genealogy & Ancestry

Bordered by IndianaKentuckyMissouri (southwest), Iowa and Wisconsin, Illinois has a land area of 57,914 square miles and a population of approximately 12,875,255. Its capital is Springfield, and the official state website is

The largest cities in Illinois are Chicago (2,695,598 residents), Aurora (197,899 residents), Rockford (152,871 residents), Joliet (147,433 residents), Naperville (141,853 residents), Springfield (116,250 residents), Peoria (115,007 residents), Elgin (108,188 residents), Waukegan (89,078 residents) and Cicero (83,891 residents).

The State of Illinois was named for the word Illini, a confederation of the Cahokia, Kaskaskia, Michigamea, Moingwena, Peoria and Tamaroa Indian tribes. Its Nickname is “Prairie State”. The State Motto is “State Sovereignty, National Union”.

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Illinois History

When Louis Jolliet and Father Jacques Marquette arrived in Illinois country in 1673, they found a settler’s paradise, with fertile soil, sweeping prairies, lush forests, and plentiful water. A traversable network of rivers, easy low-land portages, and the accessibility of Lake Michigan combined to make the future state easy to both explore and settle. Such was the economic promise of the area that in 1680, Robert Cavelier, sieur de La Salle, erected Fort Crevecoeur at the future site of Peoria.

He was accompanied by Henri de Tonti.

Two years later, the explorers also built Fort St. Louis. By 1891, Tonti, who took over the settlement with La Salle’s departure in 1685, moved it eighty miles downstream. The new fort, known as Fort Pimitoui, included several buildings, Father Marquette’s mission, and a village of fur traders’ European-native families.

Cahokia was settled by Seminarian priests in 1699, and Kaskaskia by Jesuits four years later. More settlements soon followed with Fort de Chartres, Prairie du Rocher, St. Phillipe, and St. Genevieve.

In 1717, Illinois country was placed under the French government of Louisiana. This was short-lived. France ceded all possessions east of the Mississippi in 1763, with the British taking possession in 1765. From 1778 to 1782, present-day Illinois was a territory of Virginia and known as the county of Illinois.

The American Revolution and the Treaty of Paris in 1783 extended the American boundary to the Mississippi, making it part of the United States.

The establishment of the Northwest Territory in 1787 included Illinois land which would become part of the Indiana Territory in 1800. Nine years later, the Illinois Territory was established. The region achieved statehood in 1818.

By 1800, Illinois’ population of 2,000 included Americans from Virginia, Kentucky, Maryland, Tennessee, New York, New Jersey, Pennsylvania, and New England. An influx of settlers soon followed in 1817 with a group of English immigrants who settled in Edwards County. Rhode Island Farmers also established a colony at Delavan, Tazewell County, in 1837.

Illinois had an important role in years leading up to the civil war, serving as a conduit for the Underground Railroad.

The significance of migration from Illinois should not be overlooked. Many settlers eventually left the region, moving to Kansas and Nebraska. Additionally, the gold rush to California, the wagon trains of the Oregon Trail, and the open prairies of Iowa all tempted the population of Illinois to venture still farther west.

From the late nineteenth century to the present, Chicago’s accessibility and employment possibilities attracted a cross-section of all the nationalities. Many ethnic groups either settled in or passed through the state, contributing considerably to its diversity.