Siege of Boston

Map showing Boston and the surrounding harbor
A plan of the town of Boston and its environs, with the lines, batteries, and encampments of the British and American armies. Library of Congress

While histories of the American Revolution tend to focus on just how bad the Americans had it: indeed, there is no getting around this fact; it can also be said that in the first months of the rebellion, the British army was at a continual disadvantage brought on by a series of missteps that would come to largely define how they engaged in the remainder of the war. Therefore, it can be said that when studying the Revolutionary War, there is plenty to decipher from the first shots at Lexington and Concord in April 1775 all the way to the British evacuation of Boston in March 1776. For those eleven months, the greater area was under siege.

"The Destruction of Tea at Boston Harbor" lithograph

Hostilities had finally spilled over into bloodshed between the rabble-rousers of Boston and the mother country. Long the theater of protest and division against Parliament taxation, Massachusetts had now officially crossed the threshold into a full-scale rebellion against the British Crown. The pull had not come on fast. Even after the Stamp Act in 1765 had triggered the condemnation of new taxes on the colonies, including isolated riots; even after the ‘massacre’ in Boston on March 5, 1770, spurred outrage and new patriot propaganda attacking British aggression; even after new taxes were levied to compensate for the repealing of others, Massachusetts retained their Royal identity and allegiance. Matters changed in December 1773 after members of the Sons of Liberty raided a British cargo ship and dumped costly amounts of imported tea into the harbor. It seemed the restless mobs had finally struck a nerve with British authorities: tea. In retaliation, Parliament issued the Coercive Acts which insulted and hurt the economies of many of the colonies, the Boston Port Act which closed the harbor, and stripping the colonial assemblies of any power with the Massachusetts Government Act. British commander Thomas Gage, a veteran of the French and Indian War, was placed as military governor of Massachusetts, removing the unpopular Royal governor Thomas Hutchinson. Capable and initially respected in the colonies, public support for Gage collapsed when he showed no intention of being sympathetic towards the patriot complaints. However, Gage did not seek to start a war. He granted leniency to protestors and tried several times to work with colonial leaders; actions that earned him criticism by some of his officers and members of Parliament. A large portion of Londoners mistakenly thought the majority of colonists outside of Boston despised the unruly patriots. As he tried to be diplomatic, Gage received news that munitions were being gathered and stored in various towns outside of Boston. An incident in September 1774 proved successful for British troops when they captured stored gunpowder, but the response saw the mobilization of the countryside’s militias. With Boston’s port closed, effectively destroying the main economy of the region, and putting many of out work, few people saw how this would end peacefully. 

In February 1775, Parliament gave an official address that Massachusetts was in open rebellion to the Crown. Tensions had not cooled off since the previous fall. In April, Gage received intelligence that munitions were being gathered and stored at a depot in Concord, a small hamlet west of Boston. On April 18, British cavalry were stopping colonists to ask if they knew the whereabouts of John Hancock and Samuel Adams, two of the rebellion’s leaders. The unusual display alerted many that the British were on the move. Gage had ordered a detachment of British regulars to march west to seize the munitions at Concord. As they crossed the waterways west of Boston by boat under the cover of darkness, their movements were detected by locals. In response, this would be the night, along with William Dawes and Samuel Prescott, of silversmith Paul Revere’s famous ride to warn residents. The riders quickly raced through the countryside warning residents that the redcoats were on the march. To compensate for their slow-reaction to the seizure of munitions in September, this time colonists sprang into action almost immediately. This is where the term ‘minutemen’ was coined. Lieutenant Colonel Smith sent British Major John Pitcairn with about four hundred British light infantry to march forward to Concord and seize the rebel munitions. As these troops approached the town green at Lexington, on the march to Concord, the British came upon an assembled group of militia with loaded muskets. It was just after 5 am on April 19, and standing before His Majesty’s forces were a few hundred armed colonists. No one is quite sure who fired first, but soon musket smoke filled the air. The following moments would see the British advance to Concord, be overwhelmed by colonial militia, and then witness the disillusioned British retreating back to Boston. As they did, the growing number of militia continued to fire upon the fleeing redcoats. Nearly two hundred fifty British troops were killed or wounded. The operation was a complete failure for Gage, and criticism was wielded at him by Parliament for his decision to move aggressively against Concord. And to make matters worse, the emboldened Massachusetts men were continuing to pour in and approach Boston. By June, some fifteen thousand colonists had assembled under arms around Boston Harbor. Command of this new force was given to Artemas Ward. The American Revolutionary War had officially begun.

News reached Philadelphia and the Continental Congress assembled now had to deal with the reality that Massachusetts was at war with Great Britain. On June 14, the creation of the Continental Army was ratified. But who to lead it? The following day, June 15, Virginia Colonel George Washington was nominated by Massachusetts delegate John Adams to lead the new American forces gathering in Boston. Adams, ever the politician, recognized the importance of a Virginian leading the continental forces. Washington, the only member of Congress who wore the military uniform, accepted the nomination, even if he personally felt himself unqualified for the immensity of the position.

As Washington prepared his departure to Boston, meanwhile, events continued to worsen any chance of reconciliation. The Americans had surrounded Boston on the mainland and Gage’s forces knew they had to mount an attack or face the possibility of an assault. Gage had been reinforced in late May by British generals John Burgoyne, Henry Clinton, and William Howe, along with about four thousand troops. Together, they sought the best way to fortify Boston while also driving the rebels out of the region. North of the Boston peninsula lay the small town of Charlestown, which it too sat on a peninsula that jutted out into the harbor. South of Boston lay Dorchester Heights, a ridge with a commanding view and tactical advantage for whoever held it over the entire harbor. And to the southwest of it lay the small hamlet of Roxbury, at the foot of the land-bridge with Boston. Gage’s plan was to send a detachment to establish a presence atop Dorchester Heights, and then assemble a remaining force that would march on Roxbury and push the rebels west away from Boston. Unfortunately for the British commanders, the Americans acted first. Under the command of Colonel William Prescott, about twelve hundred militia and irregular troops crossed the Charlestown neck onto the peninsula on June 16. Under the cover of night, the mixed units built a redoubt on Breed’s Hill, the larger of the two between it and Bunker Hill, which gave a clear view of Boston to the south.

This painting depicts soldiers waving their flags at the Battle of Bunker Hill.
Battle of Bunker Hill - Death of Warren

The following morning, the British command held their war council. General Henry Clinton favored a rear attack to assault the Charlestown neck, which would cut off any retreat by the Americans, and leave them surrounded on the peninsula. However, William Howe, the senior officer, who was not one to take the advice of Clinton (this would happen again), chose to attack from head-on beach invasion from the eastern bank of the peninsula. John Burgoyne concurred, assuming the rebels on the hill would scatter when approached by the British regulars. The attack commenced after 3 pm on June 17. Howe divided his army into several columns and three separate assaults took place. The Americans held their ground marvelously for the first two, sending the British regulars running back to their assembly areas. Those that did not retreat lay on the ground in bloody tangles from musket fire. The third assault concentrated the most men yet on the American redoubt on Breed’s Hill. By this point, the militia and mixed units had run out of ammunition. Soon, the British bayonet made its appearance over the wall, and the Americans pulled back. A well-organized retreat materialized in the rear and most made it back over the neck to the mainland. When the smoke began to settle, the Americans had lost over four hundred men. The British had lost over one thousand, including several senior officers.

The aftermath of the battle of Bunker Hill shattered British confidence but did not break them. The British had lost over one thousand soldiers. How could they justify it? In his official report to Parliament, Gage explained how the army fell upon so many dead of His Majesty’s troops. If known for its accuracy, the report tarnished the monarchy’s confidence in Gage, and he was replaced with General William Howe as commander in chief of forces in North America.

Washington arrived in Cambridge on July 2, and immediately took about to size up his new army. What lay before him wasn’t really an army at all. The bands of militia that were encamped were entirely ignorant of military tactics, formations, and discipline. This was not an army. This was an oversized mob. The new American commander set about establishing order, gathering provisions, and training the men. Among his subordinates were Major Generals Horatio Gates and Charles Lee, both British-born transplants who served alongside Washington in the French and Indian War; Major General Thomas Mifflin, Brigadier General Nathanael Greene, and Colonel Henry Knox, a former bookkeeper from Boston. None had really worked together on a mission whose scale was that of assembling and drilling an entire army from scratch. To complicate matters, Washington had to strategize how to dislodge the British from Boston, how to remain answerable to the wishes of Congress, how to battle elements within and without of his control (provisions remained scarce, gunpowder scarcer; there were no artillery pieces, and smallpox was hitting the crowds of men at an ever-increasing rate). It pains the imagination from our vantage point in the present day what must have been going through Washington’s mind when he walked through the ragged encampments in the first weeks of his command.

Over the course of the next several months, skirmishes broke out between small detachments of British and Continental troops. Most saw only a handful of volleys exchanged before a ceasefire would commence. Other times daring raids upended peaceful spells, and reminded the armies that a war was indeed being waged. Washington committed one thousand troops to invade Canada at the request of Congress with the hopes of routing the British garrisons at Montreal and Quebec, and bringing the vast territory into the American fold. It nearly succeeded except for an untimely defeat by exhausted American forces under Generals Richard Montgomery and Benedict Arnold at Quebec.

By winter, the British under Howe were stuck in Boston, awaiting reinforcements, and the Continental Army under Washington remained lurking on the mainland in continuous surveillance of the harbor. Of course, Washington had to contend with the daily struggles of the new army. One of the most glaring (and of which would repeatedly haunt him and Cause during the course the war) was that of enlistments. Most of the men who joined the new army had only signed on until the end of the year. That served Massachusetts well in the spring and early summer of 1775, but what of January 1, 1776, and beyond? It was one of the rare occasions where the men who walked out of camp were immediately replaced with fresh recruits. Washington would not be so lucky in the years to come. However, he now had the task of retraining his army all over again.

For a commander to be stuck in one of the best cities in the New World might seem a lucky break, but Howe had to contend with feeding his army. He had been ordered to evacuate Boston in November, but short on ships to evacuate his soldiers, and loyalist civilians in his care, he could not depart. Diseases such as smallpox and dysentery were striking both soldiers and civilians. Provisions for soldiers and horses were a constant headache for eighteenth-century military commanders. The British, being essentially trapped within the Boston peninsula, had very limited access to the wider resources available on the mainland. Transports were routinely sent out to raid whatever they could grab in haste, including oxen and thousands of sheep. Nearby islands and bars were looted for hay until Americans caught on and seized the materials for themselves. Firewood was extremely scarce, leading British troops to cut down every tree in town and dismantled several buildings. In the meantime, with the cold New England winter upon them, several of His Majesty’s troops even contemplated desertion. The British command knew they had to make a move or face the impossible: defeat.

And yet circumstances had changed once again. In October, before Parliament, King George III had declared the colonies to be in an open state of rebellion. This effectively meant hostilities would continue and likely intensify. Both sides took the news with measured restraint. What was the decisive stroke in the stalemate between armies came in the form of a storm? First, Col. Henry Knox had arrived in late January from Fort Ticonderoga with the badly needed cannon and artillery for the Continental army. Washington now saw his objective: he would establish a foothold for his artillery atop Dorchester Heights and bombard the British in Boston and the harbor below. He also devised an amphibious assault, but this was overruled by his war council. By early March, much of the artillery had been moved to Dorchester Heights. The frozen ground made digging near impossible, so the army employed carpenters to use timber to build breastworks. Out of sight of the British, on the morning of March 6, General William Howe is said to have seen the new fortifications and exclaimed, “My God, these fellows have done more work in one night than I could make my army do in three months.” Unlike the night before Bunker Hill, this time the Americans had completely surprised the British command. The assembly of fortifications at such speed cautioned the British into thinking the Americans had twenty-thousand men working on the hill alone.

Wikimedia Commons

The British tried to dislodge the American artillery, but their cannon and field pieces could not raise themselves high enough to reach the fortifications. In response, Washington, now ascending the slopes off Dorchester Heights, could be heard yelling, “Remember it is the fifth of March! Avenge the death of your brethren!” (referencing the Boston Massacre). On the opposite side of the harbor in the Charles River, nearly four thousand Continentals under the commands of Generals Greene, Israel Putnam and John Sullivan, prepared their forces to row across the harbor and land on the northern side of the Boston peninsula. Washington’s amphibious plan had finally won its day in his war council. For his part, Howe was planning to attack Dorchester Heights, a decision that many in his army questioned. Fearful of a repeat of Bunker Hill, and constantly careening their necks to gaze upward at the slopes of Dorchester, morale in the British camp was not high for the move. It seems Howe’s decision to attack came to a halt during his war council on the evening of May 6. The vote was to evacuate Boston and not engage the Americans. Overnight, a torrential storm blew in, possibly a hurricane, that upended any further chances of an impending battle. On March 8, Howe sent a letter to the American lines, asking Washington for a truce: Howe would not burn Boston to the ground if the Americans allowed him and the British to sail unmolested out of the harbor. The wish was granted, and nearly eleven thousand people boarded the British ships and transports where they departed on March 17. Hundreds of loyalists were taken to Nova Scotia and New Brunswick, Canada, where they settled and rebuilt their lives.

As for the British army under General William Howe, the loss of Boston was a temporary setback. In reality, holding the town of Boston proved to be a weak seat to command a war. His eyes settled further south toward another formidable harbor and port: New York. From a logistical standpoint, New York would serve the British far better than Boston. It was more centered in the colonies, had ample access to the Atlantic Ocean, and the Hudson River cut north toward Lake Champlain, which connected to British held Canada. If they could successfully establish a footing in New York, the British thought, they would be far more likely to gain an advantage. Washington knew this as well. And as Howe was seen leaving Boston for the Atlantic, he held no illusions where the British commander would turn up. The Continental army broke down its artillery from Dorchester Heights, and as a singular unit, marched south for New York in preparation for the campaign that lay ahead.

Had the Americans blundered and been beaten at Boston, either by a forced error on Washington’s part, or an aggressive advance by Howe; in all likelihood, the rebellion would have collapsed, and American independence would have evaporated before it could gain serious momentum. The continuing good luck from 1775 helped solidify the uniting colonists as brethren in removing British authority from North America. The very real physical and psychological effects that victory brought to the Boston region, and then spread through the continent by the printing press and word-of-mouth, helped inspire other uprisings along the coast. By the spring of 1776, all of the colonies had overthrown their Royal governments and installed patriot representatives. Even those wary of full independence had come around to the idea that the colonies could and should be allowed to govern for themselves. None of this would have been possible had Massachusetts not come under attack, and instead of submitting, citizens took up arms to repel the foreign invaders.

Founding Fathers with the Declaration of Independence
"Declaration of Independence" painted by John Trumbull in 1819.

As the summer of 1776 unfolded, the winds of change were about in Philadelphia. A spirited optimism was pushing delegates of the Continental Congress ever closer to complete independence from Great Britain. In no small part was this a testament to the oratory skill and power of Massachusetts’ John Adams. With momentum going in their direction, and with luck seemingly on their side, the New Englander made his case on July 1. Outside the statehouse in Philadelphia, a thunderstorm ravaged at the very moment he spoke, attempting to wrestle the message from the ears of the men in session. The time had come. And how poetic it was. As the opening of the great conflict had given hope to a North American world without British control, every member seated knew that with his vote, they would each be leading the emerging country into the unknown.

Further Reading

Related Battles

Massachusetts | April 19, 1775
Result: American Victory
Estimated Casualties
Massachusetts | June 17, 1775
Result: British Victory
Estimated Casualties
Massachusetts | April 19, 1775
Result: American Victory
Estimated Casualties