The Siege of Boston, which began in April 1775 and ended in March 1776, was one of the first major military engagements of the American Revolutionary War. The siege followed the initial battles of Lexington and Concord, where colonial militias clashed with British troops, signalling the start of the armed conflict between Great Britain and its thirteen American colonies.
Outbreak of Hostilities
On April 19, 1775, British troops marched from Boston to seize colonial military supplies stored in Concord. They were met with resistance from local militia at Lexington and Concord, resulting in the first skirmishes of the war. The British forces, suffering significant casualties, retreated back to Boston, where they found themselves surrounded by a growing force of colonial militia.
The Siege Begins
In the days following the battles of Lexington and Concord, thousands of colonial militia from across New England converged on Boston. They established a blockade, effectively trapping the British Army within the city. The militia, though lacking formal military training, were highly motivated and rapidly organized into a coherent fighting force under the leadership of General Artemas Ward.
Examples of key events during the siege
Battle of Bunker Hill
One of the most significant battles during the siege was the Battle of Bunker Hill, fought on June 17, 1775. Despite being a tactical victory for the British, who managed to capture the high ground, the battle proved costly. British forces suffered heavy casualties, with over 1,000 soldiers killed or wounded, demonstrating that the colonial forces were capable of standing up to the British Army.
The battle is named after Bunker Hill in Charlestown, Massachusetts, the oldest neighbourhood in Boston. A majority of the actual combat took place on an adjacent hill, now known as Breed´s Hill.
A few days prior to the battle, the colonial forces learned that the British were planning to send troops out of the city to fortify nearby hills, ultimately aiming for control of the Boston Harbor. The colonial forces, therefore, sent 1,200 troops under William Prescott to secretly occupy Bunker Hill and Breed´s Hill. Overnight, a strong redoubt went up on Breed´s Hill, and the troops also created smaller fortified lines across the Charlestown Peninsula.
It would take until daybreak on June 17 before the British realised that colonial forces were present on the Peninsula. The first two attacks on the colonial forces were successfully repulsed, but during the third assault, the colonists there ran out of ammunition. The British captured the redoubt, and the colonists retreated.
The Battle of Bunker Hill was won by the British, but the attacks resulted in a lot of British casualties – much more than what the colonists had sustained. It was also surprising to the British that several of their officers were killed, showing that the inexperienced colonist militia could successfully stand up to the British army troops and even kill officers in battle. The Battle of Bunker Hill made the British reluctant to carry out any more frontal attacks against well-defended front lines. They became more cautious, as evidenced in the New York and New Jersey campaigns. The Battle of Bunker Hill also resulted in the British Crown hiring a large number of Hessians (German soldiers of fortune) to fight the Continental Army.
Arrival of George Washington
In July 1775, George Washington arrived in Cambridge, Massachusetts, to take command of the Continental Army. Washington’s leadership was crucial in transforming the militia into a more disciplined and effective fighting force. He focused on improving the army’s organization, training, and supply situation.
Strategic developments during the siege
Fortification of Dorchester Heights
One of Washington’s key strategic moves was the fortification of Dorchester Heights in March 1776. Utilizing heavy artillery captured from Fort Ticonderoga, Washington’s forces fortified this series of low hills overlooking Boston and its harbour. The positioning of these cannons threatened the British ships in the harbour and the city itself, making the British position very vulnerable.
As a diversion, Washington ordered batteries to open fire on Boston on the night of March 2. The British returned the fire, but there were no significant casualties on either side. New, similar attacks occurred on several following nights, to keep the British focused on that and prevent them from realizing what was going on at Dorchester Heights.
It was on March 4, 1776, that troops under Washington´s command occupied Dorchester Heights and mounted powerful cannons there. Several heavy cannons from Ticonderoga were positioned at Lechmere’s Point and Cobble Hill in Cambridge, and on Lamb´s Dam in Roxbury. The project was not an easy one and it had to be carried out stealthily. The ground could not be dug because it was frozen, but Rufus Putnam, who had been a millwright, had come up with a plan that involved the use of fascines and heavy ten-feet-long timbers. These were prefabricated in advance at a spot out of sight of the British and were then hauled to Dorchester Heights, together with tools and cannon placements. In order to muffle the sounds, hay bales were placed between the hauling path and the harbour. Washington was present during this night of hard labour and boosted morale by pointing out that March 5 was the sixth anniversary of the Boston Massacre, an event where nine British soldiers had shot and killed five American colonists.
Overnight, a parapet was built overlooking Boston and its harbour. By 4 o’clock in the morning, the colonists had constructed fortifications that would withstand small arms and grapeshot. The continued work involved cutting down trees and turning them into obstacles (abatis) for approaching British forces. The colonists also prepared rock-filled barrels to be ready for the coming attack; the plan was to roll them downhill at the British troops.
Washington anticipated that General Howe, commander of the British forces in Boston, would either try to take the Dorchester Heights or leave Boston with these troops. If he had attacked, Washington´s plan was to launch an attack against the entire city from Cambridge, and he had prepared two floating batteries and enough boats to carry nearly 3,000 troops.
British Evacuation
Just like Washington had expected, General Howe understood the need to take action when he realized that Dorchester Heights had been fortified by the colonists and that powerful cannons were now threatening the harbor.
Howe initially decided to attack Dorchester Heights – but his plans were halted by a snowstorm. Faced with the formidable colonial fortifications on Dorchester Heights and the prospect of devastating artillery fire, he changed his mind and gave orders to evacuate Boston. British resupply and reinforcement were limited as they relied on sea access only. The sea had American vessels in it, and now there were also cannons pointing at the harbour.
On March 17, 1776, British troops and loyalist supporters boarded ships and withdrew to Nova Scotia. This marked the end of the Siege of Boston and was a significant early victory for the Continental Army.
Significance and impact of the Siege of Boston
The Siege of Boston was an important moment in the American Revolution for several reasons:
- Boosted Morale: The successful siege and subsequent British evacuation boosted the morale of the American forces and supporters of the revolution. It demonstrated that the colonists could successfully challenge the might of the British Army.
- Strategic Advantage: The evacuation of Boston gave the Continental Army control over a major port and city, which was crucial for receiving supplies and reinforcements.
- Leadership and Organization: The siege highlighted the importance of strong leadership and organization. Washington’s ability to rally and transform the militia into a more effective fighting force set the stage for future successes.
- International Attention: The early American successes at Boston helped garner international attention and support, laying the groundwork for future alliances, most notably with France.
Final thoughts
The 1775 Siege of Boston was a critical early engagement in the American Revolutionary War. It showcased the determination and resilience of the American forces, the strategic acumen of their leaders, and the potential for a successful resistance against British rule. The siege not only ended with the British evacuation of Boston but also marked a turning point that bolstered the American cause and set the stage for subsequent military and political efforts in the fight for independence.