Antietam
2 of the 7 encyclopedias on this shelf carry an entry for Antietam. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
an-te'tam, a small creek in Maryland fifty miles west of Washington. It flows through a wooded ravine into the Potomac a few miles below Harper's Ferry . It is noted as the scene of one of the decisive battles of the Civil War. General Lee's army, engaged in his first invasion of the North, was here turned back in a bloody battle, September 16 and 17, 1862. The Union forces were commanded by Generals McClellan, "Fighting Joe" Hooker, Sumner, Meade, Burnside, and Fitz John Porter. Noted commanders of the Confederate side were Lee, "Stonewall" Jackson, Stuart, Pickett, Hood, and Hill. Not less than 100,000 men were engaged. The carnage was terrific. Entire regiments were almost wiped out. Missing, wounded, and killed outright, the loss of both sides taken together was not far from 25,000 men. See Civil War 2026 Editor's Note: Antietam remains the bloodiest single day in American history — about 23,000 killed, wounded or missing in one September day. Its outcome gave Lincoln the victory he needed to issue the Emancipation Proclamation five days later, turning the war into a fight against slavery. The field is now a preserved national battlefield. (Ed: BR 2026-07-13)
Collier's New Encyclopedia (1921)
a small river in Pennsylvania and Maryland which empties into the Potomac six miles N. of Harper's Ferry. On Sept. 16 and 17, 1862, a battle was fought on its banks near Sharpsburg, between the Federal army of about 80,000 men, under General Mc- Clellan, and a Confederate army variously reported at from 40,000 to 97,000 men, under General Lee. The Federal aggregated 12,469, and the Confederate about 11,000. General Lee recrossed the Potomac on the following day, and the general consensus is that the battle was tactically indecisive.