ON THIS DAY ·
Battle of Antietam
17 Sep 1862 — The bloodiest single day in American history: some 23,000 casualties along a Maryland creek, and Lee’s first invasion turned back. Lincoln has the victory he has been waiting for — see the marker at Washington.
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The moment in context
Lee’s Maryland campaign and Bragg’s advance into Kentucky aimed at far more than territory, since a success on Northern or border soil might sway the autumn elections, gather border-state recruits, and encourage Britain to offer mediation. Chance then intervened when a Union soldier found a lost copy of Lee’s orders, which revealed that his army was dangerously divided. McClellan still attacked in stages at Antietam and kept large reserves idle, so Lee’s battered army was able to hold its ground and then withdraw safely, while Bragg likewise fell back after Perryville.
From Antietam and emancipation, chapter 7 of The American Civil War, 1840–1877 (SEP 1862).
The place: Battle of Antietam — map and full story →
Teach this in 5 minutes
- Why it happened — Why Lee invaded. Necessity and opportunity: Virginia’s farms were stripped and feeding his army required Northern fields. A victory on Union soil before the midterms…
- The turn — Antietam, 17 September 1862. Measure the hinge by what did NOT happen: Britain did not mediate, Maryland did not rise, the midterms did not break Lincoln, and Lee’s aura of…
- What it changed — The war acquires a second war aim. From January 1863 Union armies liberate by advancing. Hover the map’s grey-tan zones and read their notes. Garrisons, contraband camps, and the…
Then ask the room: The Proclamation freed no one in the loyal states and couldn’t be enforced where it applied. Defend the claim that it was still the war’s most important single document. The argued answer is on the chapter page →
The atlas that shows it
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