What the Army Needed to Learn

People want the Battle of Harlem Heights to be a turning point, and I understand why. After the string of disasters in August and September 1776 — Long Island, Kip's Bay, the loss of New York City — the army badly needed something it could call a win. Harlem Heights gave them that, but it is important to be precise about what kind of win it was.

It was not a strategic victory. Washington still had to retreat. New York was still lost. The British still held the ground they needed for a comfortable base of operations. By any objective military measure, September 1776 was a catastrophe for the American cause, and one battle's worth of tactical success did not change that.

What Harlem Heights did was something harder to measure. It demonstrated that American soldiers could execute a planned maneuver — a flanking movement, which requires coordination, communication, and the willingness to move through difficult terrain under pressure — and come out the better of the exchange against British regulars. That had not been proven before. Bunker Hill showed they could hold a prepared position. Harlem Heights showed they could maneuver.

I spend a lot of time thinking about what terrain meant in this campaign. People picture 18th-century Manhattan as something like Central Park — open, manicured, easy to move through. It wasn't. The northern part of the island was rocky and heavily wooded, cut by ravines and hollows, with ridges that rose sharply above the Harlem River plain. That terrain was an asset to the smaller American force and a liability to the British, whose tactical doctrine assumed open fields.

When I walk researchers through the Morris-Jumel Mansion today, I ask them to look north and west from the building's elevation. You can still see — even through the city — how commanding that position was. Washington could watch the Hudson River traffic with a glass and monitor British ship movements on the East River with a slight turn. He chose his headquarters the way a good commander chooses everything: with terrain in mind.

The army that left Harlem Heights in October 1776 was not the same army that had run from Kip's Bay. It was still in trouble — Fort Washington would demonstrate that in November. But it had learned something about itself that proved essential in the months ahead, when the situation got worse before it got better.