It was named for Stephen A. Douglas,[3] who was elected to the United States Senate in 1858, following the Lincoln–Douglas debates.

[5] As of the 2010 United States census, there were 19,980 people, 7,720 households, and 5,377 families living in the county.

There were 8,390 housing units at an average density of 20.1 per square mile (7.8/km2).

[12] In terms of ancestry, 29.6% were German, 12.6% were American, 12.1% were English, and 10.7% were Irish.

Despite its long-time Republican leanings, Hillary Clinton's 2016 performance of gaining a mere 23.8 percent of the county's vote stands over six percent worse than any Democrat since the Civil War.