On March 4, 1776 British General William Howe received word of the American position overlooking Boston. He had to wonder if Boston was defensible.
What tipped the balance was American Brigadier General John Thomas. He had slipped 2,000 troops along with cannon and plenty of supplies into Dorchester Heights the night before. The Americans had enough time to dig trenches for the artillery.
Howe had no choice but to evacuate Boston. He sailed his army to Nova Scotia. Howe stayed there until March, when he moved to New York. He engaged Washington there to disrupt the Colonials, who marched away from New York as a result.
The Dorchester Monument was erected in 1898. It is part of the Boston National Historic Park.