Philadelphia campaign The Philadelphia campaign ( 1777 – 1778 ) was a British initiative in the American Revolutionary War to gain control of Philadelphia , which was then the seat of the Second Continental Congress . British General William Howe , after unsuccessfully attempting to draw Continental Army General George Washington into a battle in northern New Jersey , embarked his army on transports , and landed them at the northern end of Chesapeake Bay . From there , he advanced northward toward Philadelphia . Washington prepared defenses against Howe ' s movements at Brandywine Creek , but was flanked and beaten back in the Battle of Brandywine on September 11 , 1777 . After further skirmishes and maneuvers , Howe was able to enter and occupy Philadelphia . Washington then unsuccessfully attacked one of Howe ' s garrisons at Germantown before retreating to Valley Forge for the winter . Howe ' s campaign was controversial because , although he successfully captured the American capital of Philadelphia , he proceeded slowly and did not aid the concurrent campaign of John Burgoyne further north , which ended in disaster at Saratoga for the British , and brought France into the war . General Howe resigned during the occupation of Philadelphia and was replaced by his second - in - command , General Sir Henry Clinton . Clinton evacuated the troops from Philadelphia back to New York City in 1778 in order to increase that city ' s defenses against a possible Franco - American attack . Washington harried the British army all the way across New Jersey , and successfully forced a battle at Monmouth Court House that was one of the largest battles of the war . At the end of the campaign the two armies were roughly in the same positions they were at its beginning . Background . Following General William Howe ' s successful capture of New York City , and George Washington ' s successful actions at Trenton and Princeton , the two armies settled into an uneasy stalemate in the winter months of early 1777 . While this time was punctuated by numerous skirmishes , the British army continued to occupy outposts at New Brunswick and Perth Amboy , New Jersey . General Howe had proposed to George Germain , the British civilian official responsible for conduct of the war , an expedition for 1777 to capture Philadelphia , the seat of the rebellious Second Continental Congress . Germain approved his plan , although with fewer troops than Howe requested . He also approved plans by John Burgoyne for an expedition to " force his way to Albany " from Montreal . Germain ' s approval of Howe ' s expedition included the expectation that Howe would be able to assist Burgoyne , effecting a junction at Albany between the forces of Burgoyne and troops that Howe would send north from New York City . Howe decided by early April against taking his army overland to Philadelphia through New Jersey , as this would entail a difficult crossing of the broad Delaware River under hostile conditions , and it would likely require the transportation or construction of the necessary watercraft . Howe ' s plan , sent to Germain on April 2 , also effectively isolated Burgoyne from any possibility of significant support , since Howe would be taking his army by sea to Philadelphia , and the New York garrison would be too small for any significant offensive operations up the Hudson River to assist Burgoyne . Howe ' s evolving plans . Washington realized that Howe " certainly ought in good policy to endeavor to Cooperate with Genl . Burgoyne " and was baffled why he did not do so . Washington at the time and historians ever since have puzzled over the reason Howe was not in place to come to the relief of General John Burgoyne , whose invasion army from Canada was surrounded and captured by the Americans in October . Historians agree that Lord Germain did a poor job in coordinating the two campaigns . Following Howe ' s capture of New York and Washington ' s retreat across the Delaware , Howe on December 20 , 1776 wrote to Germain , proposing an elaborate set of campaigns for 1777 . These included operations to gain control of the Hudson River , expand operations from the base at Newport , Rhode Island , and take the seat of the rebel Continental Congress , Philadelphia . The latter Howe saw as attractive , since Washington was then just north of the city : Howe wrote that he was " persuaded the Principal Army should act offensively [ against Philadelphia ] , where the enemy ' s chief strength lies . " Germain acknowledged that this plan was particularly " well digested " , but it called for more men than Germain was prepared to provide . After the setbacks in New Jersey , Howe in mid - January 1777 proposed operations against Philadelphia that included an overland expedition and a sea - based attack , thinking this might lead to a decisive victory over the Continental Army . This plan was developed to the extent that in April Howe ' s army was seen constructing pontoon bridges ; Washington , lodged in his winter quarters at Morristown , New Jersey , thought they were for eventual use on the Delaware River . However , by mid - May Howe had apparently abandoned the idea of an overland expedition : " I propose to invade Pennsylvania by sea . . . we must probably abandon the Jersies . " Howe ' s decision to not assist Burgoyne may have been rooted in Howe ' s perception that Burgoyne would receive credit for a successful campaign , even if it required Howe ' s help ; this would not help Howe ' s reputation , as the Philadelphia expedition would if it succeeded . Historian John Alden notes the jealousies among various British leaders , saying , " It is likely that [ Howe ] was as jealous of Burgoyne as Burgoyne was of him and that he was not eager to do anything which might assist his junior up the ladder of military renown . " Along the same lines Don Higginbotham concludes that in Howe ' s view , " [ The Hudson River campaign ] was Burgoyne ' s whole show , and consequently he [ Howe ] wanted little to do with it . With regard to Burgoyne ' s army , he would do only what was required of him ( virtually nothing ) . " Howe himself wrote to Burgoyne on July 17 : " My intention is for Pennsylvania , where I expect to meet Washington , but if he goes to the northward contrary to my expectations , and you can keep him at bay , be assured I shall soon be after him to relieve you . " He sailed from New York not long after . Early feints . Washington ' s Continental Army had been encamped primarily at Morristown , New Jersey , although there was a forward base at Bound Brook , only a few miles from the nearest British outposts . In part as a retaliatory measure against the ongoing skirmishes , General Charles Cornwallis executed a raid against that position in April 1777 , in which he very nearly captured the outpost ' s commander , Benjamin Lincoln . In response to this raid , Washington moved his army forward to a strongly fortified position at Middlebrook in the Watchung Mountains that commanded likely British land routes toward Philadelphia . For reasons that are not entirely clear , General Howe moved a sizable army to Somerset Court House , south of New Brunswick . If he performed this move as a feint to draw Washington out from his strong position , it failed , as Washington refused to move his army out in force . Washington had intelligence that Howe had not brought the necessary equipment for either bringing or constructing watercraft , so this move seemed unlikely to him to be a move toward the Delaware River . When Howe eventually withdrew his army back toward Perth Amboy , Washington did follow . Launching a lightning strike , Howe sent forces under Cornwallis in an attempt to cut Washington off from the high ground ; this attempt was foiled in the Battle of Short Hills . Howe then withdrew his troops to Perth Amboy , embarked them on transports , and sailed out of New York harbor , destined for Philadelphia . Washington did not know where Howe was going . Considering the possibility that Howe was again feinting , and would actually sail his army up the Hudson to join with Burgoyne , he remained near New York . Only when he received word that Howe ' s fleet had reached the mouth of the Delaware , did he need to consider the defense of Philadelphia . However , the fleet did not enter the Delaware , instead continuing south . Uncertain of Howe ' s goal , which could be Charleston , South Carolina , he considered moving north to assist in the defense of the Hudson , when he learned that the fleet had entered Chesapeake Bay . In August he began moving his troops south to prepare the city ' s defenses . General John Sullivan , who commanded the Continental Army ' s troops facing Staten Island , had , in order to capitalize on perceived weaknesses of the British position there following Howe ' s departure , attempted a raid on August 22 , that failed with the Battle of Staten Island . Capture of Philadelphia . General Howe landed 15 , 000 troops in late August at the northern end of the Chesapeake Bay , about 55 miles ( 90 km ) southwest of Philadelphia . General Washington positioned 11 , 000 men between Howe and Philadelphia but was outflanked and driven back at the Battle of Brandywine on September 11 , 1777 suffering over 1 , 000 casualties , while the British lost about half that number . The Continental Congress once again abandoned the city , relocating first to Lancaster , Pennsylvania , and later York , Pennsylvania . British and Revolutionary forces maneuvered around each other west of Philadelphia for the next several days , clashing in minor encounters such as the abortive Battle of the Clouds and the so - called " Paoli Massacre . " On September 26 , Howe finally outmaneuvered Washington and marched into Philadelphia unopposed . Capture of the rebel capital did not bring the end to the rebellion as the British thought it would . In 18th Century warfare , normally the side that captured the other side ' s capital city won the war . But the war was to continue for six more years ( until 1783 ) given the unconventional warfare at the time . After taking the city , the British garrisoned about 9 , 000 troops in Germantown , five miles ( 8 km ) north of Philadelphia . Washington unsuccessfully attacked Germantown on October 4 , and then retreated to watch and wait for the British to counterattack . Meanwhile , the British secured the Delaware River by taking forts Mifflin and Mercer in November ( although the latter was not taken until after a humiliating repulse ) . In early December , Washington successfully repelled a series of probes by General Howe in the Battle of White Marsh . General Washington ' s problems at this time were not just with the British . In the so - called Conway Cabal , some politicians and officers unhappy with Washington ' s performance in the campaign secretively discussed his removal . Washington , offended by the behind - the - scenes maneuvering , laid the whole matter openly before Congress . His supporters rallied behind him , and the episode was abated . Valley Forge and Monmouth . Washington and his army encamped at Valley Forge in December 1777 , about 20 miles ( 32 km ) from Philadelphia , where they stayed for the next six months . Over the winter , 2 , 500 men ( out of 10 , 000 ) died from disease and exposure . However , the army eventually emerged from Valley Forge in good order , thanks in part to a training program supervised by Baron von Steuben . Meanwhile , there was a shakeup in the British command . General Howe resigned his command , and was replaced by Lieutenant General Sir Henry Clinton as commander - in - chief . France ' s entry into the war forced a change in British war strategy , and Clinton was ordered by the government to abandon Philadelphia and defend New York City , now vulnerable to French naval power . The British sent out a peace commission headed by the Earl of Carlisle , whose offers , made in June 1778 as Clinton was preparing to abandon Philadelphia , were rejected by Congress . As the British were preparing their withdrawal , Washington sent out Lafayette on a reconnaissance mission . Lafayette narrowly escaped a British ambush at the Battle of Barren Hill . Clinton shipped many Loyalists and most of his heavy equipment by sea to New York , and evacuated Philadelphia on June 18 . Washington ' s army shadowed Clinton ' s , and Washington successfully forced a battle at Monmouth Courthouse on June 28 , the last major battle in the North . Washington ' s second - in - command , General Charles Lee , who led the advance force of the army , ordered a controversial retreat early in the battle , allowing Clinton ' s army to regroup . By July , Clinton was in New York City , and Washington was again at White Plains , New York . Both armies were back where they had been two years earlier . Aftermath . Shortly after the British arrived in New York , a French fleet arrived outside its harbor , leading to a flurry of action by both sides . The French and Americans decided to make an attempt on the British garrison at Newport , Rhode Island ; this first attempt at coordination was a notable failure . Under orders from London , Clinton reallocated some of troops to the West Indies , and began a program of raiding coastal communities from the Chesapeake to Massachusetts . Around New York , the armies of Clinton and Washington watched each other and skirmished , with occasional major actions like the 1779 Battle of Stony Point and the 1780 Battle of Connecticut Farms . Clinton considered making new attacks on Philadelphia , but these ideas never came to fruition . The British also began a wider frontier war organized from Quebec City , using Loyalist and Native American allies . British and French forces engaged each other in the West Indies and in India beginning in 1778 , and the 1779 entry of Spain into the war widened the global aspects of the war even further . In 1780 the British began a " southern strategy " to regain control of the rebelling colonies with the capture of Charleston , South Carolina . This effort would ultimately fail at Yorktown .