Fortification of Dorchester Heights

Fortification of Dorchester Heights
Part of the American Revolutionary War
Detail of a 1775 map of Boston, with Dorchester Heights at the bottom right
Date March 4–5, 1776 Location Dorchester Heights and Boston area 42°19′58″N 71°2′47″W / 42.33278°N 71.04639°W / 42.33278; -71.04639 Result British forces evacuate Boston on March 17
Belligerents
United Colonies	Great Britain
Commanders and leaders
George Washington John Thomas	William Howe
Strength
2,000–6,000 on Dorchester Heights	10,000 in Boston

The Fortification of Dorchester Heights was a decisive action early in the American Revolutionary War that precipitated the end of the siege of Boston and the withdrawal of British troops from that city.

On March 4, 1776, troops from the Continental Army under George Washington's command occupied Dorchester Heights, a series of low hills with a commanding view of Boston and its harbor, and mounted powerful cannons there threatening the city and the Navy ships in the harbor. General William Howe, commander of the British forces occupying Boston, planned an attack to dislodge them. However, after a snowstorm prevented its execution, Howe withdrew instead. British forces, accompanied by Loyalists who had fled to the city during the siege, evacuated the city on March 17 and sailed to Halifax, Nova Scotia.