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. Background The siege of Boston began on April 19, 1775, when, in the aftermath of the Battles of Lexington and Concord, Colonial militia surrounded the city of Boston. Benedict Arnold, a captain in the Connecticut militia, arrived with his troops to support the siege. He informed the Massachusetts Committee of Safety that cannons and other valuable military stores were stored at the lightly defended Fort Ticonderoga in New York, and proposed its capture. On May 3, the Committee gave Arnold a colonel's commission and authorized him to raise troops and lead a mission to capture the fort. Arnold, in conjunction with Ethan Allen, his Green Mountain Boys, and militia forces from Connecticut and western Massachusetts, captured the fort and all of its armaments on May 10. After George Washington took command of the army outside Boston in July 1775, the idea of bringing the cannons from Ticonderoga to the siege was raised by Colonel Henry Knox. Knox was eventually given the assignment to transport weapons from Ticonderoga to Cambridge. Knox went to Ticonderoga in November 1775, and, over the course of three winter months, moved 60 tons of cannons and other armaments by boat, horse and ox-drawn sledges, and manpower, along poor-quality roads, across two semi-frozen rivers, and through the forests and swamps of the sparsely inhabited Berkshires to the Boston area. Historian Victor Brooks has called Knox's successful effort "one of the most stupendous feats of logistics" of the entire war. Geography and strategy The British military leadership, headed by General William Howe, had long been aware of the importance of the Dorchester Heights, which, along with the heights