[3] The county is named for Benjamin Logan, who fought Native Americans in the area.

[4] Logan County comprises the Bellefontaine, Ohio Micropolitan Statistical Area, which is also included in the Columbus-Marion-Zanesville, Ohio Combined Statistical Area.

[5] Campbell Hill, the highest natural point in Ohio at 1,549 feet (472 m), is northeast of Bellefontaine.

As of the census[10] of 2000, there were 46,005 people, 17,956 households, and 12,730 families living in the county.

24.80% of all households were made up of individuals, and 10.30% had someone living alone who was 65 years of age or older.

As of the 2010 United States census, there were 45,858 people, 18,111 households, and 12,569 families living in the county.

[11] In terms of ancestry, 30.9% were German, 13.5% were Irish, 11.5% were American, and 9.1% were English.