21st Illinois Infantry Regiment

The 21st Regiment Illinois Volunteer Infantry was a militia infantry regiment that served in the Union Army during the American Civil War.

Service
The 21st Illinois Infantry was organized at Mattoon, Illinois and mustered into Federal service on June 28, 1861.

The regiment was mustered out on December 16, 1865.

Total strength and casualties
The regiment suffered 1 officer and 51 enlisted men who were killed in action or who died of their wounds and 2 officers and 127 enlisted men who died of disease, for a total of 181 fatalities.

Commanders

 * Colonel Ulysses S. Grant - promoted brigadier general on August 7, 1861.
 * Colonel John W.S. Alexander - killed in action September 20, 1863.