Lamb's Dam

Fortifications on or near Lamb's Dam are highlighted in this map of 1775 fortifications in Boston.

Massachusetts Historical Society, Map by Sir Thomas Hyde Page

Quick Facts

Location:

Roxbury, Massachusetts

Significance:

Fortifications during the Siege of Boston

OPEN TO PUBLIC:

No

[We] have chosen the alternative of defense and taken the field; having [furiously] and firmly resolved to devote our lives to such an important service.¹
Issac Mansfield, November 23, 1775.

In the early 1700s, Col. Joshua Lamb built Lamb's Dam in Roxbury, Massachusetts, to protect his marsh land and works at the "Salt Pans."² During the Siege of Boston, Colonial troops looked to construct fortifications around Boston to strategically push the British Army out of the city. With Lamb's Dam position on the south-west side of Boston neck, they selected this site for new fortifications. On August 23, 1775, colonial troops began construction of initial fortifications on Lamb's Dam, without interference from the British Army.³ When soldiers completed the fortification on September 10, they mounted it with four 18-pound cannons that could strike positions anywhere on Boston’s neck, making it difficult for British troops to march out of the city.⁴

Over the following six months, British and Colonial positions, including Lamb's Dam, exchanged fire without causing significant damage on either side.⁵ During this period, Colonial forces reinforced Lamb's Dam with more cannons. In hopes of bringing the siege to an end, George Washington ordered a bombardment on positions in Boston to begin on the night of March 2, 1776, and to continue through March 4. He hoped this cannon fire would distract the British Army so they would not be aware of other fortifications being built on nearby Dorchester Heights.⁶

On March 4, the fortifications on Lamb's Dam fired five 13-inch shells, six 10-inch shells, forty-two 24-pound shots, and thirty-eight 18-pound shots.⁷ Between March 2 and March 5, several houses were struck in Boston during the bombardment from all the Colonial guns, and a small boy had his leg injured. Otherwise, no significant damage occurred.⁸ While the fire was ineffective, it distracted the British Army, allowing General Knox to place artillery onto Dorchester Heights without interference.

The fortifications on Lamb's Dam succeeded in keeping the British army bottled up in Boston until they were forced to evacuate on March 17, 1776. These fortifications no longer exist today, although they would have stood close to Northampton Street in Roxbury.

Footnotes

1. Isaac Mansfield, Sermon Preached in the camp at Roxbury, November 23, 1775; Being the Day Appointed by Authority for Thanksgiving Through the Provence (Boston: S. Hall, 1776), 18.
2. Francis S. Drake, The town of Roxbury: its memorable persons and places, its history and antiquities, with numerous illustrations of its old landmarks and noted personages. (Roxbury, MA: Francis S. Drake, 1878), 309.
3. Ellis, Centennial Celebration of Evacuation of Boston, 12.
4. Richard Frothingham, History of the Siege of Boston and the Battles of Lexington, Concord and Bunker Hill. Also an account of the Bunker Hill Monument, 6^th ed. (Boston: Little, Brown, and Company, 1896), 242.
5. Timothy Newell, "A JOURNAL KEPT DURING THE TIME Y^ BOSTON WAS SHUT UP IN 1775-6," in Vol. 1 of the 4th series of Collections of the Massachusetts Historical Society (Boston: Massachusetts Historical Society, 1852), 265-70.
6. Albert Manucy. Artillery Through The Ages: A Short Illustrated History of Cannon, Emphasizing Types Used in America (Washington: United States Government Printing Office, 1949), 32.
7. Frothingham, History of the Siege of Boston 298.
8. Newell, "A JOURNAL KEPT DURING THE TIME Y^ BOSTON WAS SHUT UP IN 1775-6," 271-72.

Bibliography

Drake, Francis S. The town of Roxbury: its memorable persons and places, its history and antiquities, with numerous illustrations of its old landmarks and noted personages. Roxbury, MA: Francis S. Drake, 1878.

Ellis, George E. Centennial Celebration of Evacuation of Boston by the British Army March 17, 1776. Boston: Rockwell and Churchill, City Printers, 1876.

Frothingham, Richard. History of the Siege of Boston and the Battles of Lexington, Concord and Bunker Hill. Also, an account of the Bunker Hill Monument, 6^th ed. Boston: Little, Brown, and Company, 1896.

Heath, William. The Revolutionary War Memoirs of Major General Wiliam Heath. Edited by Sean Heuvel. Jefferson, NC: McFarland & Company, 2014.

Mansfield, Isaac. Sermon Preached in the Camp at Roxbury, November 23, 1775; Being the Day Appointed by Authority for Thanksgiving Through the Provence. Boston: S. Hall, 1776.

Newell, Timothy. "A JOURNAL KEPT DURING THE TIME Y^ BOSTON WAS SHUT UP IN 1775-6," in Vol. 1 of the 4th series of Collections of the Massachusetts Historical Society, 261-76. Boston: Massachusetts Historical Society, 1852.

Page, Thomas Hyde. Boston, its environs and harbour, with the rebels works raised against that town in 1775 / from the observations of Lieut. Page of His Majesty’s Corps of Engineers, and from the plans of Capt. Montresor. London: Wm Faden, 1778. https://www.masshist.org/database/3312.

Scudder, H. E. "The Siege of Boston," Atlantic Magazine, April, 1876, 466-481.