The American Revolutionary War’s Siege of Boston, April 19, 1775-March 17, 1776

After the April 19, 1775 Battles of Lexington and Concord, Massachusetts, the 1,700 British soldiers returned to their quarters in Boston, then a town of approximately 15,500 people in addition to the British troops. The colonial Minute Men, numbering at least 14,000 to 16,000, were gathered four miles to the west in Cambridge.

The stage was thus set for the colonists’ Siege of Boston.

Boston map, 1775
Boston map, 1775 & Today

Geography is the key to understanding this American use of the military tactic of siege, i.e., militarily surrounding a town or other place with the intent of preventing free movement to or from the place or conquering by attrition rather than by attack.

The town of Boston then was located on a peninsula surrounded on virtually all sides by the Charles River and the Boston Harbor and connected to the south mainland only by a narrow strip of land (“The Boston Neck”). (Today landfill has eliminated the Boston Neck.) Although British ships controlled the water and thus were able to resupply the British troops in the town, as they did in May 1775 with an additional 4,300 troops (for a total force of 6,000), these troops essentially were land locked.

Siege of Boston map, 1775-1776

The Americans obviously understood the British predicament, and with the Americans having the larger number of troops and not wanting to wage war in Boston, they imposed a siege of the town of Boston by stationing the militia men in a line starting in Chelsea to the northeast of Boston, going west to Charlestown and then south to Roxbury. This siege line was able to prevent the British troops from leaving Boston and engaging in war against the Americans. The Siege was an American offensive maneuver implemented for defensive purposes until the very end of the siege.

Among those participating in the Siege were Perley Brown (my maternal fifth great-grandfather) and three of his brothers–John, William and Benjamin. All four apparently had enlisted for eight months or through the balance of the year of 1775, and all except for John presumably were engaged in the Siege at least until then. John’s service unfortunately ended on June 17, 1775, when he was wounded in the Battle of Bunker Hill as we will see in a subsequent post.[1]

For most of the 11 months of siege, there were relatively minor skirmishes between the two forces except for the just mentioned Battle of Bunker Hill.

One of the skirmishes occurred in May of 1775 on Noddle’s and Hog Islands in the Harbor northeast of Boston (near today’s Boston Logan International Airport). Because of their domination of the sea, the British were using the farmers and livestock on the island to supply the British troops with fresh meat. In addition, the British were storing some naval supplies there. The colonists responded by removing livestock and hay from the islands or by killing the livestock and burning the hay and barns. On May 27 and 28, 1775, the opposing forces fought the Battle of Chelsea Creek, which was a creek between the two islands and the mainland.

The colonists without suffering any fatalities were successful in forcing the retreat of the British troops in this battle. In addition, the colonists’ cannons were able to capture and sink the British ship, HMS Diana, the first such accomplishment in the war and a big boost to their morale. One of the colonists in this military engagement was Benjamin Brown.

General George Washington
General Washington’s Headquarters, Cambridge, 1775-1776

Nearly three weeks after the Battle of Chelsea Creek, on June 14, 1775, the Second Continental Congress voted to establish the Continental Army for purposes of common defense by incorporating the 16,000 or so militia men already in action in the Boston area plus the 5,000 other men in New York. The next day (June 15th) the Congress unanimously elected George Washington as the Commander-in-Chief of the Army.

On July 3, 1775, General Washington arrived in Cambridge, Massachusetts to take command of the troops in the field. He established his headquarters and abode in a beautiful house in Cambridge that later in the 19th century was owned by the American poet, Henry Wadsworth Longfellow. (The house is now open to the public as a National Historic Site.)

On January 24, 1776, the colonists obtained a major strategic advantage with the arrival in Cambridge of over 50 heavy cannons that had been seized eight months earlier (on May 10, 1775) from the British Fort Ticonderoga at the southern end of Lake Champlain in present-day upstate New York. (The reconstructed Fort is now open to the public.)

The successful capture of the Fort was led by Ethan Allen and the Green Mountain Boys and Colonel Benedict Arnold. (Arnold in 1780 defected to the British and thereby became an infamous American traitor.)

Artillery for Boston, 1775

Between November 1775 and January 24, 1776, in a remarkable logistical operation Colonel Henry Knox and a team of engineers used boats, horse and ox-drawn sledges and manpower to transport the heavy cannons nearly 250 miles over poor roads, forest, swamps and the frozen Hudson and Connecticut Rivers to Cambridge.

Once in Cambridge, the canons were moved to Dorchester Heights overlooking Boston from the southeast. In early March 1776, the Americans started to bombard Boston with the cannons, killing some British soldiers and destroying some houses. The British returned artillery fire, but their cannons  could not reach the colonists’ weapons.

British Evacuation of Boston, 1776

After a planned British assault on the Dorchester Heights was cancelled due to a storm, the British decided to leave Boston. On March 8th General Washington received an anonymous letter saying the British would not destroy the town of Boston if they were permitted to depart without attack. Washington formally rejected the letter, but on March 17th the British evacuated Boston without hostile fire and without any destruction.

A British fleet of 120 ships with 9,906 British troops plus 1,220 women and children left Boston for the 400 mile northeastern sail to the unused British military base in Halifax, Nova Scotia.

Now in Boston March 17th is celebrated as Evacuation Day.


[1] Carol Willits Brown, William Brown–English Immigrant of Hatfield and Leicester, Massachusetts, and His Descendants c. 1669-1994 at 6, 11-27, 31-41, 50, 308-12(Gateway Press; Baltimore, MD 1994). This account of the Brown brothers’ participation is based upon two secondary sources about the town of Leicester written in the 19th century by Emory Washburn: (a) Topographical and historical sketches of the town of Leicester in the Commonwealth of Massachusetts at 49-50 (1826); and (b) Historical sketches of the town of Leicester, Massachusetts, during the first century from its settlement at 296-99(1860).

 

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As a retired lawyer and adjunct law professor, Duane W. Krohnke has developed strong interests in U.S. and international law, politics and history. He also is a Christian and an active member of Minneapolis’ Westminster Presbyterian Church. His blog draws from these and other interests. He delights in the writing freedom of blogging that does not follow a preordained logical structure. The ex post facto logical organization of the posts and comments is set forth in the continually being revised “List of Posts and Comments–Topical” in the Pages section on the right side of the blog.

11 thoughts on “The American Revolutionary War’s Siege of Boston, April 19, 1775-March 17, 1776”

  1. Comment: David McCullough on the Siege of Boston

    Noted American historian David McCullough has an interesting discussion of the Siege of Boston in his book, 1776 at 1-111 (New York; Simon & Schuster 2005).

    He emphasizes the problems General Washington faced with his troops: sickness, desertions and expiring enlistments. The Americans were very clever and surreptitious in reinforcing Dorchester Heights in March 1777 and completely surprised the British the morning after the Americans had done so. Another topic was the difficult choice faced by Loyalists in Boston when the British decided to vacate the city; 1,100 of them decided to leave with the British.

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