[5] As of the census[10] of 2000, there were 29,210 people, 10,935 households, and 7,960 families living in the county.

23.50% of all households were made up of individuals, and 10.40% had someone living alone who was 65 years of age or older.

As of the 2010 United States Census, there were 28,215 people, 10,934 households, and 7,883 families living in the county.

[12] The racial makeup of the county was 95.2% white, 0.4% black or African American, 0.4% Asian, 0.3% American Indian, 2.4% from other races, and 1.3% from two or more races.

[11] In terms of ancestry, 53.7% were German, 10.6% were Irish, 7.1% were English; 6.9% identified as "American".

From 1912 to 1936, it was a bellwether county, but starting with the 1940 election, it has become a Republican stronghold with Lyndon B. Johnson in 1964 being the lone Democrat to win since then.

The county commissioners are Lori Siclair, Glenn Miller, and Robert Hastedt.

[16] Henry County Airport is a public use airport located 3 nautical miles (6 km) east of the central business district of Napoleon, Ohio.