Jacob Preston Carnahan (September 22, 1832 – July 16, 1912) was an American Confederate officer, a professor of mathematics, and Populist politician in Arkansas.

He attended the Cane Hill School[citation needed] and graduated from Cumberland University in Lebanon, Tennessee.

[1] Carnahan was a captain in the Confederate States Army during the American Civil War, he commanded Company G of the 16th Arkansas Infantry Regiment, involved in the bloody Battle of Elkhorn Tavern, also known as the Battle of Pea Ridge.

[2][3] He was candidate for governor with the People's Party of Arkansas in 1892,[4] receiving 31,116 of 156,186 (20%) votes,[5] losing to Democrat William Meade Fishback and winning narrowly fewer votes than Republican mayor of Little Rock, William G.

He died July 16, 1912, at the home of his youngest daughter, Mrs. Susan Rogers, near Prairie Grove.