It was August 1814. Panic held New York in thrall.

After two years of incoherent fighting, the War of 1812 was being waged in deadly earnest. No longer preoccupied with the Emperor Napoleon, who had been forced to abdicate the French throne, Britain trained its full military might on the ill-prepared United States. British troops captured Washington, setting fire to the Capitol and the White House. Twilight’s last gleaming was fast approaching in Baltimore. And the enemy’s control of Lake Champlain made clear that its route to New York City would be from the poorly defended north.

Kingsbridge Road, a rudimentary highway that ran from the mainland down Manhattan Island to New York City, suddenly looked like an invasion route.

Pressed into wartime duty, civilians fashioned impromptu fortifications wherever redcoats might appear, including McGowan’s Pass in Harlem, through which anyone on the Kingsbridge Road would have to travel to reach New York.

Image A drainage trench in which the foundation of the gatehouse (large stones) and part of the Kingsbridge Road (small stones) were found. Credit... Central Park Conservancy

On the north side of the pass, the citizens drilled a line of holes into a rock outcropping. Iron rods inserted in those holes could have been used to help build a defensive wall linking three small fortifications — Fort Clinton, Nutter’s Battery and Fort Fish — that guarded the pass and the surrounding countryside.