Under the cover of constant bombing from American artillery, Brigadier General John Thomas slips 2,000 troops, cannons and artillery into position at Dorchester Heights, just south of Boston, on March 4, 1776. Under orders from General George Washington, Thomas and his troops worked through the night digging trenches, positioning cannons and completing their occupation of Dorchester Heights.
The cannon that made Thomas’ efforts possible were those taken by Lieutenant Colonel Benedict Arnold and Ethan Allen with his Green Mountain Boys at Fort Ticonderoga on May 10, 1775. Colonel Henry Knox then brought the cannon and powder to Boston through the winter snow in time for Washington and Thomas to employ them in the engagement at Dorchester Heights.
By muffling their wagon-wheels with straw, the Patriots were able to move their cannon unnoticed. Washington would use this same strategy to evade British General Charles Cornwallis after the Battle of Trenton.
At daybreak, British General William Howe received word of the American position overlooking the city. Within days, General Howe came to realize that the American position made Boston indefensible and soon ordered the evacuation of all British troops from the city; the British sailed for Halifax, Nova Scotia, on March 17. Howe and his troops remained in Canada until they traveled to meet Washington in the conflict over New York in August.
In 1898, a Georgian white marble revival tower was commissioned for the site of the battle to memorialize the Patriot victory at Dorchester Heights. The memorial tower has been listed on the National Register of Historic Places since 1966. In 1978, it joined eight other sites in the Boston National Historic Park under the purview of the National Park Service.