Illinois (unspecified)

State of Illinois's geographic center, or that point on which a surface of uniform thickness would balance, for the state is located in Logan County, 45 km (28 mi) northeast of Springfield.

statehood: 3 December 1818. "Illinois" comes from the name of a confederacy of several Indian tribes recorded by the French with a plural ending. The original Indian word meant "the men". The name was transferred to a river and the Territory. (US-T131/1976/DOI - U.S. Geological Survey (USGS) News Release: Origin of Names of U S States)