Reconnaissance of the Fortifications on the Northern Part of New York Island for Which Principal Points Were Geometrically Identified on July 22 and 23


This manuscript map in pen-and-ink and watercolor was created in July 1781 by a French military cartographer engaged in reconnaissance work during the final stages of the American Revolutionary War. The map is oriented with north to the right. The British captured New York in September 1776. In the summer of 1781, General George Washington, commander of the Continental Army, considered an attack on New York, but he and the Comte de Rochambeau instead feigned preparations for an attack on the city while stealthily moving their troops to Yorktown, Virginia. There, the British under General Charles Cornwallis (1738–1805) were forced to surrender in what proved to be the climactic battle of the Revolutionary War. The map depicts British defenses at King’s Bridge and its vicinity. An alphabetical legend on the left side indexes Fort Washington, Fort Laurel Hill, Fort Tryon, Fort Charles, redoubt “no. 8,” the quarters of the dragoons and the Hessians, and destroyed or abandoned works built by the Americans. Also shown are roads, ferries, some houses, vegetation, and relief. The scale is in toises, an old French unit measuring about 1.95 meters. The map is from the Rochambeau Collection at the Library of Congress, which consists of 40 manuscript maps, 26 printed maps, and a manuscript atlas that belonged to Jean-Baptiste-Donatien de Vimeur, comte de Rochambeau (1725‒1807), commander in chief of the French expeditionary army (1780‒82) during the American Revolution. Some of the maps were used by Rochambeau during the war. Dating from 1717 to 1795, the maps cover much of eastern North America, from Newfoundland and Labrador in the north to Haiti in the south. The collection includes maps of cities, maps showing Revolutionary War battles and military campaigns, and early state maps from the 1790s.

Title in Original Language

Reconnoissance des ouvrages du nord de l'Isle de Newyork dont on a déterminé géometriquement les principaux points le 22 et le 23 juillet

Type of Item

Physical Description

1 map : manuscript, pen-and-ink and watercolor ; 46 x 54 centimeters


  • Scale approximately 1:10,300


  1. John R. Sellers and Patricia Molen Van Ee, compilers, Maps and Charts of North America and the West Indies, 1750‒1789: A Guide to the Collections in the Library of Congress (Washington, DC: Library of Congress, 1981).

Last updated: February 18, 2016