Illinois State Geological SurveyThis polygon data layer represents the boundary for Illinois in 1998. The dataset was originally published by the Illinois State Geological Survey in 1998.[This is an Arc/Info polygon and arc data set showing the state line boundary of Illinois. Nominal scale is 1:62,500.]Shapefileark:/77981/gmgs0r9m35pengPublicBoundary Illinois {1998}DatasetsIllinois1998American Geographical Society Library – UWM Libraries