[4] The county is named for General William Henry Harrison, who was later President of the United States.

The county was named after General William Henry Harrison, the hero of the battle of Tippecanoe in the War of 1812 (and later to become the ninth U.S. president).

[7] On May 16, 2013, the Chicago Tribune Business section reported that the Utica Shale underlying Harrison County shows promise as a tight oil production zone.

[8] To produce tight oil in large quantities would require horizontal drilling and fracturing of the shale formation as is being done in North Dakota and Texas.

The paved multi-use trail is 11.4 miles (18.3 km) long.

As of the census[15] of 2000, there were 15,856 people, 6,398 households, and 4,516 families living in the county.

25.6% of all households were made up of individuals, and 13% had someone living alone who was 65 years of age or older.

As of the 2010 United States Census, there were 15,864 people, 6,526 households, and 4,452 families living in the county.

[16] In terms of ancestry, 20.9% were German, 15.5% were Irish, 9.0% were English, 8.9% were American, and 5.7% were Polish.