The Battles of Lexington and Concord, fought on April 19, 1775, marked the beginning of armed conflict in the American Revolutionary War. The British Army, numbering approximately 700 regulars under Lieutenant Colonel Francis Smith, received orders to seize and destroy military supplies stored by the colonial militia in Concord. Anticipating this move, colonial leaders, including Paul Revere and Samuel Prescott, alerted local militias, leading to a rapid mobilization of forces. As the British troops advanced, they encountered about 80 militiamen in Lexington, led by Captain John Parker. The confrontation resulted in the deaths of eight militiamen, including Ensign Robert Munroe, while the British suffered only one casualty. The British forces then proceeded to Concord, where they searched for supplies but found most had been relocated. At the North Bridge, approximately 400 militiamen engaged 100 British regulars, resulting in casualties on both sides and forcing the British to retreat.

As the British began their return march to Boston, they faced increasing resistance from the growing number of colonial militias, which had swelled to about 4,000 men. The British, now outnumbered and under constant fire, struggled to maintain their formation. Lieutenant Colonel Smith was wounded, and Major John Pitcairn took command as the British column faced ambushes and skirmishes along the route. The retreat became chaotic, with British soldiers suffering significant casualties from the relentless attacks of the colonial militias, who utilized the terrain to their advantage. The British forces were eventually reinforced by Brigadier General Earl Percy, who led about 1,700 men back to Boston under heavy fire, marking a tactical withdrawal that culminated in a blockade of Boston by the militias.

The engagements at Lexington and Concord resulted in approximately 49 British casualties, including killed and wounded, while colonial forces suffered around 95 casualties. The battles galvanized support for the Patriot cause, leading to a significant increase in militia enlistment and the establishment of a siege around Boston. The events of that day are often referred to as the 'shot heard round the world,' symbolizing the start of the American Revolution and the struggle for independence from British rule.

The Siege of Boston commenced on April 19, 1775, following the Battles of Lexington and Concord, when Massachusetts militias encircled the city, effectively blocking land access. Under the command of General George Washington, who was appointed by the Continental Congress, the Continental Army grew as reinforcements from New Hampshire, Rhode Island, and Connecticut arrived. The British, led by General Thomas Gage, fortified their positions within Boston, establishing defenses with ten 24-pound cannons in Roxbury and fortifying key hills. Despite their efforts, the British faced significant supply shortages due to American privateers disrupting their maritime logistics, leading to dwindling food and resources for the garrisoned troops.

On June 17, 1775, the British launched an assault during the Battle of Bunker Hill, aiming to seize the high ground on the Charlestown peninsula. Although they succeeded in capturing Bunker Hill, they incurred heavy casualties, with approximately 1,000 British soldiers killed or wounded, including 92 officers. This battle marked a turning point, as it demonstrated the resolve of the American forces despite their tactical defeat. Throughout the siege, skirmishes and minor engagements continued, with the Americans employing sharpshooters to harass British positions, while Washington worked to organize and strengthen the Continental Army.

In late 1775, Washington ordered Colonel Henry Knox to transport heavy artillery from Fort Ticonderoga to Boston. By January 1776, Knox successfully delivered 60 tons of cannons, which were strategically positioned on Dorchester Heights. On March 4, 1776, the Americans began bombarding Boston, prompting British General William Howe to recognize the untenable nature of his position. On March 17, 1776, the British evacuated Boston, taking over 11,000 personnel, including troops and loyalists, to Halifax, Nova Scotia. This marked the end of the eleven-month siege, with the Americans regaining control of the city and solidifying their position in the Revolutionary War.

The capture of Fort Ticonderoga took place on May 10, 1775, when a force of approximately 83 Green Mountain Boys, led by Ethan Allen and Colonel Benedict Arnold, launched a surprise attack on the fort, which was garrisoned by a small British contingent of two officers and 46 men from the 26th Regiment of Foot. The Americans crossed Lake Champlain under the cover of darkness, arriving at the fort just before dawn. The only sentry on duty fled after misfiring his musket, allowing the Americans to enter the fort unopposed. Allen and Arnold quickly roused the sleeping British troops at gunpoint, and after a brief confrontation, Captain William Delaplace surrendered the fort without any casualties, although one American was slightly injured. Following the capture, the Americans plundered the fort for supplies, including liquor, while Arnold struggled to assert his authority over the unruly Green Mountain Boys.

On May 11, a small detachment under Seth Warner captured Fort Crown Point, which was only lightly defended. The exact date of this capture is debated, with some accounts suggesting it occurred on May 10. Concurrently, Arnold organized a raid on Fort Saint-Jean on the Richelieu River, which he executed on May 14 with a force of 50 men. They successfully seized military supplies and the British warship HMS Royal George, which Arnold renamed the Enterprise. This operation was conducted swiftly, as Arnold's forces were warned of approaching British reinforcements and managed to escape with their spoils. The capture of Ticonderoga and subsequent actions disrupted British communications between their northern and southern forces and provided the Continental Army with much-needed artillery for the siege of Boston.

Throughout the operation, tensions arose between Allen and Arnold regarding command and credit for the capture. Arnold, who had received formal authorization from the Massachusetts Committee of Safety, found it difficult to exert control over the Green Mountain Boys, who were loyal to Allen. This rivalry continued to escalate, with both leaders attempting to claim credit for the successful operation. Arnold's efforts to catalog the military equipment at Ticonderoga were complicated by the chaotic atmosphere following the capture, as the fort's condition had deteriorated over time. Despite the initial success, the internal conflicts among the American forces highlighted the challenges of leadership and coordination in the early stages of the Revolutionary War.

The Battle of Chelsea Creek occurred on May 27 and 28, 1775, as part of the Boston campaign during the American Revolutionary War. The engagement took place in Chelsea Creek and the surrounding salt marshes and islands of Boston Harbor, northeast of the Boston peninsula. The American forces, primarily composed of Colonel John Stark's 1st New Hampshire Regiment, aimed to disrupt British supply lines by seizing livestock and hay from Noddle's Island and Hog Island. Stark's regiment, numbering around 300 men, crossed the Mystic River shortly after midnight on May 27, moving undetected to Hog Island, where they began rounding up livestock. A smaller group, led by Stark, forded Crooked Creek to Noddle's Island, where they set fire to haystacks and barns, prompting a British response.

Vice-Admiral Samuel Graves, commanding the British naval forces, dispatched approximately 400 marines to Noddle's Island after noticing smoke from the burning hay around 2 PM. The British schooner Diana, commanded by Lieutenant Thomas Graves, was sent to support the marines and cut off the colonists' escape. The American forces initially retreated to Crooked Creek, where they took defensive positions and engaged in a pitched battle with the British marines. The colonists managed to hold their ground until they regrouped and moved back to Hog Island, successfully driving hundreds of livestock to the mainland. As night fell, the British attempted to rescue the stranded Diana, but American forces, bolstered by General Israel Putnam and additional troops, engaged them with cannon fire from the shore.

By around 10 PM, the British were forced to abandon their efforts to save the Diana, which subsequently ran aground. Lieutenant Graves and his crew evacuated to the sloop Britannia, while American forces boarded the Diana, removing valuable supplies and setting the ship ablaze around 3 AM on May 28 to prevent its recapture. The battle resulted in no American fatalities, though British casualties were reported variably, with some sources claiming as many as 300 killed or wounded. The successful capture and destruction of the Diana marked a significant morale boost for the American forces and was notable for being the first naval capture of the war.

The Battle of Machias, also known as the Battle of the Margaretta, occurred from June 11 to June 12, 1775, near the port of Machias, Maine. Following the outbreak of the American Revolutionary War, British authorities enlisted Loyalist merchant Ichabod Jones to supply troops besieged in Boston. On June 2, 1775, Jones arrived in Machias with two merchant ships, Unity and Polly, accompanied by the British armed sloop HMS Margaretta, commanded by Midshipman James Moore. The townspeople opposed Jones' intentions and arrested him, while Moore managed to escape. The townspeople seized Unity, armed it, and prepared to confront Moore, who had refused to surrender when demanded by the militia.

On June 11, 1775, after regrouping, Colonel Benjamin Foster led approximately 20 men to East Machias, where they fortified Unity and commandeered a local schooner, Falmouth Packet. The militia pursued Margaretta, which had suffered damage and was unable to navigate effectively. Jeremiah O'Brien, elected captain of Unity, led his crew to intercept Margaretta. As Moore attempted to escape, he engaged in a brief exchange of fire with the militia. Ultimately, O'Brien's crew boarded Margaretta, where a fierce battle ensued. Moore was fatally shot, and his second-in-command surrendered the vessel and crew after sustaining heavy casualties, including three British crew members killed and several others wounded.

The aftermath of the battle saw the British crew held in Machias for a month before being transferred to the Massachusetts Provincial Congress. The Machias militia suffered two fatalities and several injuries. Anticipating British retaliation, the local community sought assistance from the Massachusetts Provincial Congress, which organized their defense. Jeremiah O'Brien outfitted one of the captured vessels as Machias Liberty, and in July 1775, he and Foster captured two more British schooners. The British attempted to retaliate later in the war but were unsuccessful in subduing Machias, which became a significant staging point for American privateering efforts against British supply lines.

The Battle of Bunker Hill occurred on June 17, 1775, during the Siege of Boston, marking a significant early engagement in the American Revolutionary War. The colonial forces, numbering approximately 1,200 men under Colonel William Prescott, occupied Breed's Hill and constructed a redoubt overnight in anticipation of a British assault. The British, led by General William Howe, launched their attack after discovering the colonial fortifications. The first two assaults, aimed at the colonial positions, were repelled with heavy British casualties, as the colonists withheld their fire until the enemy was within close range. The British suffered significant losses, including many officers, and were forced to retreat after their initial attempts to capture the redoubt failed, with the colonists benefiting from the high ground and their defensive preparations.

As the battle progressed, the British regrouped and launched a third assault, this time concentrating their forces on the redoubt. The British troops, now stripped of unnecessary equipment, advanced in column formation, which reduced their exposure to colonial fire. This final attack succeeded in capturing the redoubt, but at a high cost; Major John Pitcairn was killed during the assault, and the colonial defenders, having run out of ammunition, were forced to retreat. The colonial forces managed a controlled withdrawal, with many troops escaping over Bunker Hill to fortified positions in Cambridge, although they left behind artillery and supplies. The British ultimately gained control of the peninsula but suffered approximately 1,054 casualties, including 226 dead, while colonial losses were around 450, with 140 killed, including notable figures such as General Joseph Warren.

The battle demonstrated the capability of colonial militia to stand against British regulars, leading to a reassessment of British tactics in subsequent engagements. The high casualty rate among British officers prompted a more cautious approach in future operations, while the colonial forces recognized the need for better organization and supply management. The events of Bunker Hill would influence military strategies on both sides as the conflict continued to unfold.

The Battle of Gloucester occurred on August 8 or 9, 1775, during the American Revolutionary War, when Captain John Linzee of the Royal Navy's sloop-of-war HMS Falcon engaged in a skirmish at Gloucester, Massachusetts. On the morning of August 8, Linzee spotted two American schooners attempting to sail for Salem. He successfully captured one without incident and then pursued the second, which, familiar with the local waters, grounded itself near Five Pound Island in Gloucester Harbor shortly after noon. Linzee ordered a local fisherman to pilot the Falcon and the captured schooner into the harbor and dispatched 36 men in three small boats, led by his lieutenant, to seize the grounded vessel. Among the crew were ten impressed Americans, including four from Gloucester.

The arrival of the British ship prompted the townspeople to raise the alarm, and militia companies, led by Captains Joseph Foster and Bradbury Sanders, mustered to defend their town. Armed with muskets and two swivel guns, they opened fire on the British boats as they approached the schooner. The British rowed quickly and boarded the grounded vessel but found themselves under constant fire from the shore. Linzee attempted to distract the militia by firing the Falcon's guns at the town and sent a landing party to burn it, but this effort was unsuccessful. The lieutenant was wounded, and by 4 PM, he and a few men managed to escape in a skiff, leaving the remaining British sailors trapped. By 7 PM, all small boats had been captured, and Linzee suspected that the crew of the captured schooner had overpowered the prize crew, ultimately recovering the vessel.

Linzee's actions at Gloucester were part of a series of events that led to a retaliatory expedition by Captain Henry Mowat in October 1775. Mowat's mission included plans to target Gloucester, citing Linzee's defeat as justification, although he ultimately chose not to attack due to the town's layout. The subsequent major action of Mowat, the Burning of Falmouth, played a significant role in prompting the Second Continental Congress to establish the Continental Navy.