In what year was Illinois admitted to the Union?

Illinois was admitted to the Union on December 3, 1818. This marked a significant moment in the formation of the United States, as it was part of the westward expansion that occurred during the early 19th century. By becoming the 21st state, Illinois played a key role in the development of the Midwest region and contributed to the growing cultural and economic landscape of the nation.

The other years given in the choices do not correspond to Illinois statehood. The year 1700 predates the establishment of Illinois as a territory, while 1900 and 1850 are both years that do not have significance in the context of Illinois entering the Union, with the former being well beyond statehood and the latter occurring during a period of territorial organization rather than state admission.