The 91st 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 91st Illinois Infantry was organized at Camp Butler, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

 and mustered into Federal service on September 8, 1862.

The regiment was mustered out on June 12, 1865 and discharged at Chicago, Illinois on June 28, 1865.

Total strength and casualties

The regiment suffered 12 enlisted men who were killed in action or who died of their wounds and 1 officer and 131 enlisted men who died of disease, for a total of 144 fatalities.