Still holding one of the most notorious records in terms of casualties in American history, the Civil War garnered around 1,100,000 casualties and claimed around 620,000 lives.
Largely considered as one the deadliest conflict in U.S. history, the Civil War ravaged America with roughly a 2.5 percentage of the American population dying in it, 40 percent of which the bodies were never identified. The average death rate for all Civil War soldiers in this time raised to a staggering 1 out of 5.