Penobscot Expedition The Penobscot Expedition was an American naval expedition sent to reclaim Maine , which the British had conquered and renamed New Ireland . It was the largest American naval expedition of the American Revolutionary War and is the United States ' worst naval defeat until Pearl Harbor . The fighting took place both on land and on sea , in what is today Castine , Maine . The defeat of the Expedition was one of the greatest British victories of the war . In June 1779 , British Army forces under the command of British General Francis McLean established a series of fortifications centered on the British fort , Fort George , located on the Majabigwaduce Peninsula in Penobscot Bay , with the goals of establishing a military presence on that part of the coast and beginning a new colony to be known as New Ireland . In response , the state of Massachusetts , with some support from the Continental Congress , raised an expedition to drive the British out . The Americans landed troops in late July and attempted to establish a siege of the Fort George in a series of actions seriously hampered by disagreements over control of the expedition between Commodore Dudley Saltonstall and General Solomon Lovell . For two weeks British General Francis McLean held off the assault until a British fleet under the command of Sir George Collier arrived on August 13 , driving the American fleet to total self - destruction up the Penobscot River . The survivors of the American expedition were forced to make an overland journey back to more - populated parts of Massachusetts with minimal food and armament . Background . Following partially successful raid of Machias in 1777 , as well as General John Burgoyne ' s failed Saratoga campaign , British war planners looked for other ways to gain control over the rebellious New England colonies , while most of their effort was directed at another campaign targeted at the southern colonies . Lord Germain , the Secretary of State responsible for the war effort , and his under - secretary , William Knox , wanted to establish a base on the coast of the District of Maine ( which was then a part of Massachusetts ) that could be used to protect Nova Scotia ' s shipping and communities from American privateer s and raiders . Opportunity arrived when John Nutting , a Loyalist who had piloted Sir George Collier ' s expedition against Machias , came to London with the idea of establishing a British military presence in Maine . In September 1778 , Nutting left for New York carrying orders for Lieutenant General Sir Henry Clinton to assist with the establishment of " a province between the Penobscot and St . Croix rivers . Post to be taken on Penobscot River . " It was Knox ' s idea to call this province New Ireland . Unfortunately for the British , Nutting ' s ship was captured by an American privateer , and he was forced to dump his dispatches , putting an end to execution of the idea in 1778 . British forces arrive . Nutting reached New York in January 1779 , but General Clinton had received copies of the orders from other messengers . Clinton had already assigned the expedition to General Francis McLean , who was based in Halifax , so he sent Nutting there with Germain ' s detailed instructions . McLean ' s expedition set sail from Halifax on May 30 , 1779 , and arrived in Penobscot Bay on June 12 . The next day McLean and Andrew Barkley , the captain of the naval convoy , identified a suitable site at which they could establish a post . On June 16 , his forces began landing on a peninsula that was then called Majabigwaduce ( now Castine ) , between the mouth of the Bagaduce River and a finger of the bay leading to the Penobscot River . The troops numbered approximately 700 : 50 men of the Royal Artillery and engineers , 450 of the 74th Regiment of ( Highland ) Foot and 200 of the 82nd ( Duke of Hamilton ' s ) Regiment . These began to build a fortification on the peninsula , which jutted into the bay and commanded the principal passage into the inner harbor . The principal works , called Fort George , was in the center of the small peninsula , with two batteries outside the fort to provide cover for the , which was the only ship expected to stay in the area . A third battery was constructed on an island south of the bay in which " Albany " was harbored , near the mouth of the Bagaduce River . Construction of the works occupied the troops for the next month , until rumors came that an American expedition was being raised to oppose them , following which efforts were redoubled to have works suitable for defense against the Americans prepared before they arrived . " Albany " captain , Henry Mowat , who was familiar with Massachusetts politics , took the rumors ( which were followed by reports that a fleet had left Boston ) quite seriously , and convinced General McLean to leave additional ships that had been part of the initial convoy as further defense . Some of the convoy ships had already left ; orders for armed sloops " North " and " Nautilus " were countermanded before they were able to leave . American reaction . When news of this reached the American authorities in Boston , they hurriedly made plans to drive the British from the area . The Penobscot River was the gateway to lands controlled by the Penobscot Indians , who generally favored the British . Congress feared that if a fort were successfully constructed at the mouth of the river , all chance of enlisting the Penobscots as allies would be lost . Massachusetts was also motivated by the fear of losing their claim over the territory to rival states in any post - war settlement . To spearhead the expedition , Massachusetts petitioned Congress for the use of three Continental Navy warships — the 12 - gun sloop " Providence " , 14 - gun brig " Diligent " , and 32 - gun frigate " Warren " — while the rest of over 40 ships were made up of ships of the Massachusetts State Navy and private vessels under the command of Commodore Dudley Saltonstall . The Massachusetts authorities mobilized more than 1 , 000 militia , acquired six small field cannons , and placed Brigadier General Solomon Lovell in command of the land forces . The expedition departed from Boston on July 24 and arrived off Penobscot Bay that same day . Landing . On July 25 , nine of the larger vessels in the American flotilla exchanged fire with the Royal Navy ships from 3 . 30 p . m to 7 . 00 p . m . While this was going on , seven American boats approached the shore for a landing but turned back when enemy fire killed an American - allied Native warrior in one of the boats . On July 26 , Lovell sent a force of Continental Marines to capture the British battery on Nautilus Island ( also known as Banks Island ) , while the militia were to land at Bagaduce . The marines achieved their objective but the militia turned back when British shot overturned the leading boat , drowning Major Daniel Littlefield and two of his men . Meanwhile , 750 men under Lovell landed and began construction of siege works under constant fire . On July 27 , the American artillery bombarded the British fleet for three hours , wounding four men aboard . Assault . On July 28 , under heavy covering fire from the " Tyrannicide " , the " Hunter " and the " Sky Rocket " , Brigadier General Peleg Wadsworth led an assault force of 400 ( 200 marines and 200 militia ) ashore before dawn at Dyce ' s Head on the western tip of the peninsula with orders to capture the British fort . They landed on the narrrow beach and advanced up the steep bluff leading to the fort . The British pickets , who included Lieutenant John Moore , put up a determined resistance but received no reinforcement from the fort and were forced to retire , leaving the Americans in possession of the heights . Eight British troops were captured . At this point , Lovell ordered the attackers to halt and entrench where they were . Instead of assaulting the fort , Lovell had decided to build a battery within " a hundred rods " of the British lines and bombard them into surrender . The American casualties in the assault had been severe : " one hundred out of four hundred men on the shore and bank " , with the Continental Marines suffering more heavily than the militia . Commodore Saltonstall was so appalled by the losses incurred by his marines that he refused to land any more and even threatened to recall those already on shore . Siege . On July 29 , 1 American was killed . On July 30 , both sides cannonaded each other all day . On July 31 , 2 American sailors belonging to the " Active " were wounded by a shell . On August 1 , Lovell ordered a night assault on the Half - Moon Battery , next to Fort George , whose guns posed a danger to the American shipping . The Americans opened fire at 2 . 00 a . m . Colonel Samuel McCobb ' s center column , comprising his own Lincoln County Regiment , broke and fled as soon as the British returned fire . The left column comprising Captain Thomas Carnes and a detachment of marines , and the right column comprising sailors from the fleet , both kept going and stormed the Battery . As dawn broke , the Fort ’ s guns opened up on the captured battery and a detachment of redcoats charged out and recaptured the Half - Moon , routing the Americans , who took 18 prisoners with them . Their own casualties were 4 men missing ( who were killed ) and 12 wounded . The siege continued with minor skirmishing . On August 2 , militiaman Wheeler Riggs , of Falmouth , was killed by an enemy cannon shot that bounced off a tree before hitting him . On August 4 , Surgeon John Calef recorded in his journal that several men were wounded in exchanges of fire . On August 5 , one American - allied Indian was killed and another man captured . On August 7 , 100 Americans engaged 80 British but the only casualties were 1 killed and 1 wounded on the American side and 2 wounded among the British . During this time , the British had been able to send word of their condition , and request reinforcements . On August 3 , British commander George Collier led a fleet of 10 warships out of New York . On August 11 , about 250 American militia advanced from their fortified camp and occupied a recently abandoned battery about a quarter mile ( 400 meters ) from the British fort . As expected , a sortie of about 55 British troops advanced from the fort to engage : but the poorly trained American troops fired only one volley at the attacking British troops , inflicting about 13 casualties , and fled back to their fort , leaving behind all of their arms and equipment . The next day , Saltonstall finally decided to launch a naval attack against the British fort , but Collier in command of the British relief fleet arrived and attacked the American ships . Over the next two days , the American fleet fled upstream on the Penobscot River , pursued by the Collier . On August 13 , an American officer was wounded by enemy fire . Several vessels were scuttled or burned along the way with the rest destroyed at Bangor . In the 18th century there were rapids at Bangor at the approximate location of the old Water Works . The surviving crews then fled overland back to Boston with virtually no food or ammunition . Casualties . Over the course of the siege , Colonel David Stewart claims the British garrison suffered 25 killed and 34 wounded . Stewart gives no figures for captured or missing but 26 prisoners are known to have been taken by the Americans . Apart from the 100 men killed and wounded during the assault of July 28 , the known American casualties throughout the siege came to 12 killed , 16 wounded and 1 captured , in addition to " several wounded " on August 4 . This adds up to at least 130 killed and wounded . The " History of Penobscot " says that " our whole loss of men was probably not less than 150 " . The chaotic retreat however , brought the American loss up to 474 killed , wounded , captured or missing . Aftermath . A committee of inquiry blamed the American failure on poor coordination between land and sea forces and on Commodore Saltonstall ' s failure to engage the British naval forces . Saltonstall was declared to be primarily responsible for the debacle , and he was court - martialed , found guilty , and dismissed from military service . Paul Revere , who commanded the artillery in the expedition , was accused of disobedience and cowardice . This resulted in his dismissal from the militia , even though he was later cleared of the charges . Peleg Wadsworth , who mitigated the damage by organizing a retreat , was not charged in the court martial . The British evacuated the area pursuant to the terms of the 1783 Peace of Paris , abandoning their attempts to establish New Ireland . During the War of 1812 the British again occupied the area they called New Ireland , and used it as a naval base before withdrawing again with the arrival of peace . Full ownership of present - day Maine ( principally the northeastern borders with New Brunswick ) remained disputed until the Webster - Ashburton Treaty in 1842 . Maine was a part of Massachusetts until 1820 , when it was admitted into the Union as the 23rd state . Legacy . In 1972 the Maine Maritime Academy and the Massachusetts Institute of Technology searched for and found the wreck of the " Defence " , a privateer that was part of the American fleet . Evidence of scuttled ships has also found under the Joshua Chamberlain Bridge in Bangor and under the Bangor town dock , and several artifacts were recovered . Cannonballs were also reported to have been recovered during the construction of the concrete casements for the I - 395 bridge in 1986 . The earthworks of Fort George still stand at the mouth of the Penobscot River in Castine , accompanied by concrete work added later by the Americans in the 19th century . Archaeological evidence of the expedition , including cannonballs and cannon , was located during an archaeological project in 2000 – 2001 .