The 40th Iowa Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War.

The regiment was mustered out on June 5, 1865.

A total of 1136 men served in the 40th Iowa at one time or another during its existence.

[1] It suffered 19 enlisted men who were killed in action or who died of their wounds and 2 officers and 184 enlisted men who died of disease, for a total of 205 fatalities.

This article about a specific military unit of the American Civil War is a stub.