Siege of Boston, 1775-1776
The Siege of Boston (April 19, 1775 – March 17, 1776) stands as one of the opening and most consequential military engagements of the American Revolutionary War, during which Continental Army forces under General George Washington surrounded and ultimately compelled the evacuation of British troops garrisoned in the city of Boston, Massachusetts. Lasting nearly eleven months, the siege transformed Boston from a seat of colonial tension into the first major theater of armed conflict between American colonists and the British Crown, establishing military and political precedents that would shape the course of the revolution. The successful conclusion of the siege on March 17, 1776 — a date still commemorated in Massachusetts as Evacuation Day — marked the first significant American military victory of the war and demonstrated that organized colonial forces could challenge and defeat a professional European army.
History
The roots of the Siege of Boston stretch back through years of escalating colonial discontent, driven by Parliamentary taxation measures, the presence of British troops in the city, and the increasingly assertive response of Massachusetts patriots. By the spring of 1775, Boston had become the epicenter of revolutionary agitation in the American colonies. The city's harbor had been effectively closed by the Intolerable Acts following the Boston Tea Party of 1773, and the stationing of British regulars under General Thomas Gage had created a charged atmosphere of mutual suspicion between the occupiers and the civilian population. When British forces marched toward Lexington and Concord on the night of April 18 and into the early hours of April 19, 1775, the first shots of the Revolutionary War were fired, and the siege of Boston began in earnest.
In the immediate aftermath of Lexington and Concord, colonial militiamen from across Massachusetts and neighboring colonies converged on the outskirts of Boston, forming a rough cordon around the Charlestown and Boston peninsulas. Although disorganized at first, this gathering force effectively trapped the British garrison inside the city. The Battle of Bunker Hill on June 17, 1775 — technically fought on Breed's Hill in Charlestown — provided the British with a pyrrhic tactical victory, as they successfully took the hill but suffered devastating casualties that underscored the formidable resolve of the colonial militias. The engagement demonstrated to both sides that the conflict would not be easily or quickly resolved.
When the Continental Congress formally established the Continental Army and appointed George Washington as its commander-in-chief in June 1775, Washington arrived outside Boston in early July to find a sprawling but poorly equipped army. Over the following months, Washington worked to impose military discipline, organize supply lines, and develop a coherent strategy for dislodging the British. The chronic shortage of gunpowder and artillery presented the most serious challenge to any offensive action. The resolution to this problem came through an audacious winter expedition led by Henry Knox, a Boston bookseller turned artillery officer, who oversaw the transport of cannons captured at Fort Ticonderoga in upstate New York across the frozen landscape of New England, hauling the heavy guns on sleds through the Berkshire Mountains and down to the Boston area.
The arrival of the Ticonderoga artillery in late February 1776 gave Washington the means to act decisively. On the night of March 4 and into the early morning of March 5, 1776 — the anniversary of the Boston Massacre — colonial forces under cover of darkness fortified Dorchester Heights, a strategic promontory overlooking Boston Harbor and the British fleet anchored within it. Working through the night with extraordinary speed, the Americans erected earthworks and positioned the newly acquired cannons, transforming the heights into a commanding strongpoint. When British commander General William Howe, who had replaced Gage, awoke on the morning of March 5, he found the American guns trained on his ships and the city itself. Reportedly stunned by the speed and scale of the fortification, Howe famously remarked that the Americans had accomplished in a single night what his own forces could not have done in a month.
Faced with an untenable military situation, Howe negotiated an informal agreement with Washington by which the British would evacuate Boston without destroying the city, in exchange for being allowed to depart unmolested. On March 17, 1776, approximately 9,000 British troops and roughly 1,100 Loyalist civilians boarded ships and sailed out of Boston Harbor, bound initially for Halifax, Nova Scotia. Washington's army entered the city to find it largely intact, though stripped of supplies and resources by the departing British forces. The liberation of Boston was celebrated throughout the colonies as a signal victory and bolstered colonial confidence at a critical early stage of the war.[1]
Geography
Boston's physical geography played a decisive role in the character and outcome of the siege. The city in 1775 occupied a narrow peninsula connected to the mainland by a thin isthmus known as the Boston Neck, making it relatively easy for colonial forces to contain the British garrison without needing to assault the city directly. The surrounding landscape of hills, harbors, and inlets created a complex tactical environment in which control of high ground was paramount. The harbor, while providing the British with a maritime lifeline for resupply and potential evacuation, also represented a vulnerability — any force commanding the heights surrounding it could threaten the fleet with artillery fire.
Charlestown, located on a peninsula north of Boston across the Charles River, became the site of some of the most intense early fighting, culminating in its burning by British forces during the Battle of Bunker Hill. To the south, Dorchester and its prominent heights overlooked not only the city but also the main anchorage of the British fleet, making it the most strategically significant piece of ground in the theater. The decision to occupy Dorchester Heights proved to be the decisive geographical move of the entire siege. The surrounding towns of Cambridge, Roxbury, and Brookline served as the primary bases of operation for the Continental Army, with Cambridge hosting the headquarters where Washington established his command.
The waterways surrounding Boston — the Charles River, the Mystic River, Boston Harbor, and the various channels threading between the harbor islands — shaped movement, logistics, and communication throughout the siege. The British relied on their naval superiority to maintain contact with the outside world and to move troops between points within the harbor system, while American forces could not directly challenge this advantage and instead focused on controlling the landward approaches and, ultimately, the commanding heights.
Culture
The Siege of Boston left a lasting cultural imprint on the city and on Massachusetts as a whole. The events of 1775 and 1776 were experienced not merely as a military campaign but as a profound civic and communal ordeal. Thousands of Boston residents who were unable or unwilling to live under British occupation had fled the city prior to and during the siege, dispersing into the surrounding countryside and altering social and family networks across the region. Those who remained behind endured food shortages, the commandeering of private property, and the constant tension of military occupation. Loyalist residents, by contrast, faced the prospect of reprisal and social ostracism if they remained after the British evacuation.
The commemoration of the siege became a matter of civic identity for Boston and Massachusetts. Evacuation Day, observed on March 17, became an official public holiday in Suffolk County, Massachusetts — a designation that coincidentally aligns with Saint Patrick's Day, reflecting the significant Irish-American population of Boston and the county. The Dorchester Heights monument, erected in South Boston in the nineteenth century, stands as a permanent reminder of the strategic maneuver that decided the siege. The events of 1775 and 1776 are woven into the broader cultural narrative of Boston as a city of revolutionary heritage, a theme reflected in the city's many historical sites, museums, and public commemorations.[2] The Freedom Trail, a walking route connecting sixteen historic sites across central Boston, includes several locations directly associated with the siege and its precursor events, drawing visitors from around the world to engage with the physical landscape of the revolution.
Attractions
Several sites associated with the Siege of Boston remain accessible to the public and form part of the city's broader landscape of revolutionary heritage. Dorchester Heights, now known formally as Thomas Park, is administered as part of the Boston National Historical Park and features the neoclassical marble monument constructed in 1902 to commemorate Washington's decisive fortification of the heights. The site offers commanding views of Boston Harbor and the surrounding neighborhoods of South Boston, allowing visitors to appreciate the tactical significance of the position that effectively ended the siege.
The Bunker Hill Monument in the Charlestown neighborhood marks the site of the June 1775 battle that, while a British tactical success, proved a moral and strategic turning point in the early siege. The monument, an Egyptian Revival obelisk completed in 1843, is also part of Boston National Historical Park and includes a museum at its base. Visitors may climb the 294 steps to the top of the obelisk for panoramic views of the city, harbor, and surrounding region. Nearby, the USS Constitution, a later vessel but one closely associated with American naval heritage, is moored at the Charlestown Navy Yard and attracts substantial visitor interest.[3]
Cambridge preserves the Longfellow House–Washington's Headquarters National Historic Site, the Georgian mansion that served as Washington's headquarters during the siege. Now operated by the National Park Service, the house interprets both Washington's military tenure and its later associations with the poet Henry Wadsworth Longfellow. Together, these sites form a coherent network of revolutionary-era landmarks that allow residents and visitors alike to trace the physical geography of the siege across the present-day metropolitan area.