Here's the question word for word:

On September 17, 1862, what Maryland battle has the dubious distinction of being the bloodiest of the civil war?

The date and the state would lead you to say "Antietam." Antietam was the bloodiest one-day battle.

Gettysburg is the bloodiest battle of the Civil War.

http://www.nps.gov/archive/anti/casualty.htm

Antietam is the 8th bloodiest battle of the Civil War but the bloodiest one-day battle.

DeSota

Great facts DeSota. But, with the Date of the conflict clearly in the question. Antietam is the only answer that works. There is no problem with the 'bloodiest' phrase in the question either... as you pointed out, it WAS the bloodiest one-day battle. Ultimately, nothing incorrect in question or answer. good post, though.

Besides Gettysburg National Military Park is located in Adams County, Pennsylvania. The question was started with: What "MARYLAND" battle...