[2] Henderson County is part of the Burlington, IA–IL Micropolitan Statistical Area.

[5] As of the 2010 United States Census, there were 7,331 people, 3,149 households, and 2,127 families residing in the county.

[14] As part of Yankee-settled Northern Illinois, Henderson County was solidly Whig in its first three elections and then equally Republican from that party's formation until the Great Depression.

Republican Donald Trump carried the county with over 61 percent of the vote in 2016; the highest percentage won by any Republican candidate since Dwight D. Eisenhower in 1956, and for then Democratic opponent Hillary Clinton, it was the lowest by a Democrat since Al Smith in 1928.

Henderson County is located in Illinois's 17th Congressional District and is currently represented by Democrat Cheri Bustos.

The county is located in the 47th district of the Illinois Senate, and is currently represented by Republican Jil Tracy.