John J. Hardin (born January 6, 1810, died February 23, 1847) was a U.S. Representative from Illinois, son of Martin Davis Hardin. Born in Frankfort, Kentucky, Hardin pursued classical studies and was graduated from Transylvania University, Lexington, Kentucky. He studied law. He was admitted to the bar in Kentucky in 1831 and commenced practice in Jacksonville, Illinois. He served in the Illinois Militia during the Black Hawk War 1831-1832. He was brigadier general in command during the Mormon trouble in Hancock County in 1844 and later attained the rank of major general. He was appointed prosecuting attorney of Morgan County in 1832. He served as member of the State house of representatives 1836-1842. Hardin was elected as a Whig to the Twenty-eighth Congress (March 4, 1843-March 3, 1845). He was not a candidate for renomination in 1844. During the Mexican War recruited the First Regiment, Illinois Volunteer Infantry, of which he was commissioned colonel. He was killed at the Battle of Buena Vista, Mexico, February 23, 1847. He was interred in City Cemetery (East), Jacksonville, Illinois.
