The 20th Regiment Illinois Volunteer Infantry was an infantry

Infantry

Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

 regiment

Regiment

A regiment is a major tactical military unit, composed of variable numbers of batteries, squadrons or battalions, commanded by a colonel or lieutenant colonel...

 that served in the Union Army

Union Army

The Union Army was the land force that fought for the Union during the American Civil War. It was also known as the Federal Army, the U.S. Army, the Northern Army and the National Army...

 during the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

.

Service

The 20th Illinois Infantry was organized at Joliet, Illinois

Joliet, Illinois

Joliet is a city in Will and Kendall Counties in the U.S. state of Illinois, located southwest of Chicago. It is the county seat of Will County. As of the 2010 census, the city was the fourth-most populated in Illinois, with a population of 147,433. It continues to be Illinois' fastest growing...

 and mustered into Federal service on June 13, 1861 for a three year enlistment.

The regiment was mustered out of service on July 16, 1865.

Total strength and casualties

The regiment suffered 7 officers and 132 enlisted men who were killed in action or who died of their wounds and 1 officer and 191 enlisted men who died of disease, for a total of 331 fatalities.

Commanders

• Colonel
  Colonel
  Colonel , abbreviated Col or COL, is a military rank of a senior commissioned officer. It or a corresponding rank exists in most armies and in many air forces; the naval equivalent rank is generally "Captain". It is also used in some police forces and other paramilitary rank structures...
  
   C. Carroll Marsh
  C. Carroll Marsh
  Charles Carroll Marsh was a Union Army officer during the American Civil War. He served with distinction early in the war at the battles of Fort Donelson and Shiloh. He is commonly referred to as "C. Carrol Marsh" in official reports.-Early life:...
  
   -resigned on April 22, 1863.
• Colonel Daniel Bradley - discharged February 13, 1865.
• Lieutenant Colonel
  Lieutenant colonel
  Lieutenant colonel is a rank of commissioned officer in the armies and most marine forces and some air forces of the world, typically ranking above a major and below a colonel. The rank of lieutenant colonel is often shortened to simply "colonel" in conversation and in unofficial correspondence...
  
  Henry King - mustered out with the regiment.