Once inhabited by Cahokia mound builders and Illini Indians, the Illinois Country was settled by French Canadians and governed by Louisiana until 1763. England then ruled the land east of the Mississippi, and American forces took it in 1778. Settlers came from Kentucky, and Virginia, Maryland, and Pennsylvania, and as part of the Northwest Territory, slavery was prohibited. All these changes prompted some people to move westward, across the Mississippi. It became part of the Indiana Territory from 1800 to 1809, and was then Illinois Territory until statehood in 1818.

Connected by rivers, lakes, canals, the National Road, and eventually railways, Illinois became a hub of national travel and commerce. Trapping, farming, mining and production of all types contributed to the growth of the new state.

This guide offers a selection of resources and strategies for Illinois local history and genealogy research. These include the print and digital collections of the Library of Congress, as well as external repositories and web sites key to finding forebears in the Prairie state, also known as the Land of Lincoln.