Order of battle of the Battle of Long Island The Battle of Long Island was a decisive British victory early in the American Revolutionary War over American forces under the command of Major General George Washington , and the opening battle in a successful British campaign to gain control of New York City in 1776 . The Americans had lined New York ' s harbor with various levels of entrenchment and fortification , which were defended by an array of Continental Army forces and militia companies from New York and nearby states . After the British made an unopposed landing on Long Island in mid - August , Washington reinforced forward positions in the hills of central Brooklyn . The British forces were led by Lieutenant General William Howe , and included veterans of the Siege of Boston , new regiments from Ireland , and hired German troops from Hesse - Kassel . On August 27 , 1776 , Howe made a successful flanking maneuver around the American left while occupying the American right with diversionary battle . As a result , a significant portion of the American army became entrapped and surrendered after its retreat to the entrenched position was cut off . With a siege of the position looming , General Washington successfully withdrew his remaining army to Manhattan in the early hours of August 29 . British and Hessian forces . The British Army at the start of the campaign was drawn from three sources . The first was troops that had been in the Siege of Boston , which ended when the British evacuated their troops from the city to Halifax , Nova Scotia in March 1776 . The second was new levies raised in the British Isles , including a significant number of Irish troops . The third was troops provided by several small German principalities of the Holy Roman Empire . After the war broke out in 1775 , the British government realized that it would need more troops than it could raise on its own to fight the war , so it sought to hire troops from willing third parties in Europe . Only a few German rulers were willing to provide troops . The single largest contingent , with more than 12 , 000 arriving in North America in 1776 , came from the Landgraviate of Hessen - Kassel . All of the German troops with the British at the start of the New York campaign were from Hesse - Kassel , and were under the command of Lt . Gen . Leopold Philip von Heister . A regiment from Waldeck that was also destined for the New York theater did not arrive until after Manhattan was occupied . Some of the troops sent from Europe had first been directed at operations in the southern colonies , under the direction of Lt . Gen . Henry Clinton . The expedition attempted to occupy Charleston , South Carolina , but was repulsed in the June Battle of Sullivan ' s Island ; it then sailed for New York to join the army as it gathered on Staten Island in July and August . Clinton served as General Howe ' s second in command . It was common practice at this time for regiments of the British Army to include companies of light infantry and grenadier s , composed of troops with specialized abilities and training . When an army was assembled , these companies were often separated from their regiments and formed into separate light infantry and grenadier battalions . The Royal Navy , despite dominating the harbor , played only a limited role in the battle . HMS " Roebuck " penetrated as far as Red Hook on August 26 , but her guns never came within range of American positions . The navy did provide some logistical support for the battle . It resupplied General James Grant ' s troops with gunpowder and ammunition late in the battle , and also landed 2 , 000 Royal Marines to share in the victory . The primary source for this data is a return of troops prepared by General Howe on August 22 , 1776 , five days before the battle , and presented by historian David Hackett Fischer . Howe ' s report did not include a breakdown of individual unit sizes . Although a more detailed return for August 27 appears to have once existed , none of the listed sources reproduces it . According to a summary of that return , the strength of the British land forces under Howe ' s command was 24 , 464 fit for duty . This number does not include a brigade of Loyalist s raised by Oliver De Lancey , Sr . , or the marines , who were not under Howe ' s command . Howe ' s headcount , including officers and those unfit for duty , came to 31 , 625 . The casualty figures for British units are from a casualty - only return prepared by General Howe , reprinted by Field . It includes a detailed breakdown by unit of British casualties , and a summary of Hessian casualties . American forces . The troops arrayed to oppose the British were primarily from regiments of the Continental Army , although there were a large number of militia units from New York , Connecticut , New Jersey , and Pennsylvania in the field as well . A significant number of the Continentals had participated in the Siege of Boston , after which they had moved to join troops already in New York preparing its defenses . Some troops had participated in the expeditions against Quebec begun in fall 1775 . That attempt ended in June 1776 after a disastrous retreat to Fort Ticonderoga prompted by the arrival of a large British force at Quebec City , and some of those troops were then rushed south to assist in New York . The American defense of Long Island became complicated when Major General Nathanael Greene fell ill on August 15 . He had directed the defense work on Long Island , and was thus the general most familiar with the terrain . Washington replaced him on August 20 with Major General John Sullivan , lately returned from Ticonderoga . After sending reinforcements onto Long Island on August 25 , Washington replaced Sullivan with the ranking major general , Israel Putnam . David Hackett Fischer observes that the American command situation was " [ s ] o tangled [ . . . ] that units were uncertain about their commanders and not sure of the positions they were to defend . " The basis for this order of battle is a return prepared by General Washington on August 3 . It encompasses all of the units stationed in the New York area , not only those involved in the battle . The total provided is a listing of " all " troops , not just those listed as ready for duty . A substantial number of troops were sick during July and August . For example , General William Heath , writing in his memoirs , recorded that about 10 , 000 men were sick on August 8 , and Washington reported on September 2 having fewer than 20 , 000 men present and fit for duty . Later returns were apparently impossible : Washington wrote to Congress on August 26 that " [ t ] he shifting and changing which the regiments have undergone of late has prevented their making proper returns , and of course puts it out of my power to transmit a general one of the army . " The notes for each unit give some indication of where it was stationed , and what sort of movements it made , especially between August 22 and 29 , a time period in which there were several significant movements and reassignments of troops . A number of units were moved from Manhattan to Long Island after the British landing on Long Island , and more were sent over during and after the fighting to bolster the defenses before they were finally abandoned on August 29 . Detailed American casualties are not available because many of the relevant records were destroyed by fire in 1800 . British and Hessian estimates placed the total American losses at around 3 , 000 , and a return prepared by General Howe listed 1 , 097 prisoners , including Generals John Sullivan , Lord Stirling , and Nathaniel Woodhull . Casualty numbers for specific units are rare ; historian John Gallagher has compiled a partial listing confirming 1 , 120 killed or missing , noting that returns for 52 of 70 units under Washington ' s command are missing . The Maryland Regiment of William Smallwood was virtually wiped out , suffering 256 killed and more than 100 captured out of a unit numbering nearly 400 . Casualty figures are listed as notes if they are available for a given unit .