The county boundaries in Illinois are where two county lines within the state meet. As of 2015, such boundaries exist between the counties of Sangamon and Christian, Warren and Henderson, Knox and Fulton, Greene and Jersey, and Saint Clair and Monroe. Some counties also border other states.Continue Reading
The Illinois capitol of Springfield is in Sangamon County, and Menard County, Logan County, Macon County and Morgan County are other counties that border this county. As of 2014, the population estimate is 198,997 for Sangamon County and 33,982 for Christian County. Taylorville is one of the towns in Christian County.
Warren County has approximately 17,874 residents, and it's neighbor, Henderson County, has 6,916. The west border of Henderson County lies on the Mississippi River, with the State of Iowa on the other side. The counties of Knox and Fulton also exist in western Illinois, with Knox having an estimated population of 52,069 and Fulton County having an estimated 36,007 residents.
Greene and Jersey Counties are in the southwest portion of the state, and these counties have population estimates of 13,434 and 22,571 respectively. Saint Clair County has an estimated population of 265,729, while neighboring Monroe County has an estimated population of 33,722 residents.Learn more about The Midwest