The strategic importance of Dorchester Heights was well understood by both the British and the Colonials. The British originally intended to attack it at the same time that they attacked Bunker Hill in June 1775. There is speculation that the losses suffered at Bunker Hill dissuaded them from making another attack.
Like Bunker Hill, whichever combatant that held it would control Boston Harbor. British control would mean that the harbor would remain open for shipping and the British could move in and out of Boston as they pleased. Colonial control would significantly reduce the British use of the harbor and make it nearly impossible for them to remain in Boston.
Washington wanted to attack the British since he arrived in Boston. However, his council of war that included Generals Horatio Gates, Nathaniel Greene, William Heath, Israel Putnam, Joseph Spencer, and Artemus Ward and the occasional delegate from Continental Congress like John Adams or Benjamin Franklin repeatedly guided against an all out attack. They knew that the Colonial army was not prepared for an all out attack nor did they want to destroy Boston to remove the British. Once it became clear that Henry Knox's efforts at Ticonderoga had been successful the council agreed to an offensive plan.
The plan they devised was to take Dorchester Heights. They would move the guns that had recently been retrieved from Ticonderoga and build a fortress. However, a reconnaissance mission found the ground too frozen and hard to attempt to build a fortress by moving earth as they had done on Bunker Hill. The solution to this problem was proposed by Lieutenant Rufus Putnam. He informed Colonel Richard Gridley and Henry Knox. The three men then presented the idea to Washington. Washington accepted the plan, which was to build the fortress in Cambridge and then transport it. Hundreds of men started building timber frames as soon as the decision was made.
The plan was executed flawlessly. On Saturday night, March 2, the colonial army started to bombard the British position in Boston with cannons from Ticonderoga that had been placed at Roxbury, Cobble Hill, and Lechmere Point. The bombardment served two purposes. Distract the British from the real intent and drown out the noise of the work preparing to move the fortress and cannons. Bombardments continued on Sunday March 3 and Monday March 4. 2,000 colonial troops moved the guns and fortress into place while others distracted the British. Once the fortress was complete the troops that worked through the night were relieved by another 3,000 fresh troops. When the British awoke on March 5, they were shocked to see a fortified colonial fort on top of a hill that was empty when they went to bed the night before.
The British planned to remove the Colonials by force. As they were assembling the troops, a Nor'easter rolled into Boston bringing rain, snow, and large winds. Unable to attack in the storm and having already received orders to leave Boston, the British determined to evacuate rather than fight. The evacuation of Boston was a major win for the Colonials. March 17 is still celebrated as a holiday in Boston. The official reason for the holiday is Evacuation Day, it also happens to be St. Patrick's Day.
The summit of Dorchester Height was excavated for material to build up Boston in the late 1800s.
1898 Massachusetts commissions building of monument at Dorchester Heights
1927 Monument added to mark Henry Knox trail
1966 Added to National Registry of Historic Places
1978 Transferred to the National Park Service to become part of the Boston National Historic Park
Dorchester Heights monument is located in Dorchester, MA. See map below.
Do you have a great story about this? Share it!