It is named for Edward Preble, a naval officer who fought in the American Revolutionary War and against the Barbary Pirates.

[4] As of the 2010 United States census, there were 42,270 people, 16,341 households, and 11,867 families living in the county.

[16] In terms of ancestry, 34.3% were German, 14.6% were Irish, 12.7% were American, and 11.5% were English.

[19] As of the census[20] of 2000, there were 42,337 people, 16,001 households, and 12,144 families living in the county.

20.60% of all households were made up of individuals, and 8.90% had someone living alone who was 65 years of age or older.

Preble County votes for Republicans more often than Democrats in presidential elections.

It only supported a Democrat for president five times in the 20th century, the last being Lyndon Johnson in 1964.

Jimmy Carter is the last Democrat to tally as much as 40 percent of the vote.