Constructed in 1814, long before the Park even existed, the Blockhouse is the oldest building in Central Park.

The stone structure was one of several built to defend New York from the British during the War of 1812. After the British attacked Stonington, Connecticut, in August 1814, New Yorkers became fearful of a similar attack from the north. They quickly sprang into action and constructed defensive forts overlooking the lower lands of Harlem. The British never came to New York, and the forts never saw battle. Most were taken down; the Blockhouse was the only one to survive. After the war, military features like its sunken wooden roof and mobile cannon were removed.

Park designers Calvert Vaux and Frederick Law Olmsted left the fort as a picturesque ruin covered in vines.