[2] In February 1844, Hardin was present on the USS Princeton when one of its guns exploded, and he helped manage the aftermath of the disaster, staying on the ship for nearly a week.

[3] It has been suggested that Hardin's premature death helped Lincoln's rise to prominence in Illinois politics.

[4] Despite being an unabashed Whig, Hardin was a fervent supporter of the Mexican–American War that was advocated by James K. Polk and many expansionist Democrats.

On February 23, 1847, he was killed at the Battle of Buena Vista, Mexico, after attempting to lead a charge against a Mexican battery.

This article incorporates public domain material from Hardin, John J. Biographical Directory of the United States Congress.