It was named for John A. Logan (1826-1886), a Civil War general and United States Senator from Illinois.

King became the county seat briefly in 1899 before Napoleon once again was given that title.

[5] The Logan County terrain consists of rolling hills, dotted with lakes and ponds.

[6] The terrain slopes to the east, with its highest point near its southwestern corner at 2,133 ft (650 m) ASL.

Logan County voters have traditionally voted Republican.

In no national election since 1936 has the county selected the Democratic Party candidate.