People of German ancestry fought on both sides in the American Revolution. Many of the small Holy Roman Empire states in Europe supported the British. King George III of Britain was simultaneously the ruler of the German Electorate of Hanover. Around 30,000 Germans fought for the British during the war, around 25% of British land forces. In particular, 12,000 Hessian soldiers served as Auxiliaries on the side of British. However some Germans who were supporters of Congress as individuals crossed the Atlantic to help the Patriots.

Inside America, German Americans were largely concentrated in Pennsylvania and upstate New York. The majority supported Congress and the patriot cause. Very few German Americans were Loyalists, although many of the religious sects (such as the Amish) were neutral. It is estimated that nearly 5,000 of the German auxiliaries permanently settled in the United States.

European allies of Britain

Germans in Europe lived in numerous separate states. Some of these states had been in alliance with Britain during the Seven Years' War, and were eager to assist Great Britain. Britain had used auxiliary forces in every one of its 18th century wars, their use in suppressing rebellion seemed consistent with previous policy. Their use against British subjects was controversial, however. Despite British Whig opposition to using German soldiers to subjugate the "sons of Englishmen," Parliament overwhelmingly approved the measure in order to quickly raise the forces need to suppress the rebellion.

The leasing of soldiers to a foreign power was also controversial to some Europeans, but the people of these continental states generally took great pride in their soldiers' service in the war. Prussia notably rejected the request to send soldiers. Germans living in America did not enlist in the auxiliary units but some enlisted in British units. The 60th (Royal American) Regiment recruited both from the Americas and from Germany.

The sudden demand to rent thousands of auxiliaries placed a burden on recruiters. Base standards had to be met, including a minimum height and number of teeth required to operate flintlock muskets. Recruiters could be forced to pay losses due to desertion or loss of equipment. As many as 40,000 German auxiliaries were sent to North America, Gibraltar, Minorca and Mysore, and South Africa. In North America, German units accounted for more than a third of British forces.

Americans were alarmed at the arrival of hired German fighters. Several American representatives to Continental bodies declared they would be willing to declare independence if King George used such soldiers against them. The hired German troops were referred to as mercenaries by the patriots.Taylor, 2016, p. 359 Patriot outrage was also reflected in the Declaration of Independence:

Colonial-era jurists drawing a distinction between auxiliaries and mercenaries, with auxiliaries serving their prince when sent to the aid of another prince, and mercenaries serving a foreign prince as individuals., page 1. By this distinction, the troops which served in the American Revolution were not mercenaries, but auxiliaries. Early Republican historians, however, defended the term "mercenaries" to distinguish the foreign, professional armies from the idealized citizen soldier who altruistically fought for independence. Mercy Otis Warren promoted the idea of German auxiliaries as barbarians, but also as victims of tyranny.

Throughout the war, the United States attempted to entice the hired men to stop fighting. In April 1778, Congress issued a letter, addressed "To the officers and soldiers in the service of the king of Great Britain, not subjects of the said king", which offered land and livestock to defecting German units, in addition to increased rank. At the conclusion of the war, Congress offered incentives—especially free farmland—for these ethnic Germans to remain in the United States.Eelking, 259 Great Britain also offered land and tax incentives to its Loyalist soldiers willing to settle in Nova Scotia in present-day Canada.

Hesse-Kassel

The financial basis of some smaller continental states was the regular rental of their regiments to fight for various larger nations during the 18th century.The Hessian Mercenary State: Ideas, Institutions, and Reform under Frederick II, 1760-1785, Ingrao, Charles W. (2003) The Landgraviate of Hesse-Kassel, in particular, was economically depressed, and had "rented" out professional armies since the 17th century, with general support from both upper and lower classes. This allowed Hesse-Kassel to maintain a larger standing army, which in turn gave it the ability to play a larger role in European power politics. Hesse-Kassel pressed eligible men into service for up to 20 years, and by mid-18th century, about 7% of the population was in military service. The Hessian army was very well trained and equipped; its troops fought well for whoever was paying their prince.

The Landgraviate of Hesse-Kassel was under Frederick II, a Roman Catholic and an uncle of King George III. He initially provided over 12,000 soldiers to fight in the Americas. Like their British allies, the Hessians had some difficulty acclimatizing to North America; the first troops to arrive suffered from widespread illness, which forced a delay in the attack on Long Island. From 1776 on, Hessian soldiers were incorporated into the British Army serving in North America, and they fought in most of the major battles, including those of New York and New Jersey campaign, the Battle of Germantown, the Siege of Charleston, and the final Siege of Yorktown, where about 1,300 Germans were taken prisoner, although various reports indicate that the Germans were in better spirits than their British counterparts.

Because the majority of the German-speaking troops came from Hesse, modern Americans sometimes refer to all such troops of this war generically as "Hessians". It has been estimated that Hesse-Kassel contributed over 16,000 troops during the course of the Revolutionary War, of whom 6,500 did not return.Eelking, 257 Hessian officer (later General) Adam Ludwig Ochs estimated that 1,800 Hessian soldiers were killed, but many in the Hessian army intended on staying in America, and remained after the war.Eelking, 258 Captain Frederick Zeng, for example, served out his term with the armies of Hesse-Kassel and remained in the United States, even becoming an associate of Philip Schuyler.

Hesse-Kassel signed a treaty of alliance with Great Britain to supply fifteen regiments, four grenadier battalions, two jäger companies, and three companies of artillery.Eelking, 16 The jägers in particular were carefully recruited and well paid, well clothed, and free from manual labor.Jägers were offered a signing bonus of one Louis d'or coin, which was increased to four Louis d'or as Hesse tried to fill its companies with expert riflemen and woodsmen. These jägers proved essential in the "Indian style" warfare in America, and Great Britain signed a new treaty in December 1777 in which Hesse-Kassel agreed to increase their number from 260 to 1,066.

German-speaking armies could not quickly replace men lost on the other side of the Atlantic, so the Hessians recruited African-Americans as soldiers, known as Black Hessians. There were 115 black soldiers serving with Hessian units, most of them as drummers or fifers. It is estimated that 20% of the people serving in Hessian units were not Hessians.

Perhaps the best-known officer from Hesse-Kassel is General Wilhelm von Knyphausen, who commanded his troops in several major battles. Other notable officers include Colonel Carl von Donop (mortally wounded at the Battle of Red Bank in 1777) and Colonel Johann Rall, who was fatally wounded at the Battle of Trenton in 1776. Rall's regiment was captured, and many of the soldiers were sent to Pennsylvania to work on farms.

The war proved longer and more difficult than either Great Britain or Hesse-Kassel had anticipated, and the mounting casualties and extended supply lines took a political and economic toll. Following the American Revolution, Hesse-Kassel would end the practice of raising and leasing armies.

Hesse-Hanau

Hesse-Hanau was a semi-independent appendage of Hesse-Kassel, governed by the Protestant Hereditary Landgrave William, eldest son of the Roman Catholic Frederick II of Hesse-Kassel. When William received news of the Battle of Bunker Hill in 1775, he unconditionally offered a regiment to King George III. During the course of the war, Hanau provided 2,422 troops; only 1,441 returned in 1783. A significant number of Hessian soldiers were volunteers from Hanau, who had enlisted with the intention of staying in the Americas when the war was over.

Colonel Wilhelm von Gall is one well-known officer from Hesse-Hanau;Manfred von Gall: Hanauer Journale und Briefe aus dem Amerikanischen Unabhängigkeitskrieg 1776-1783 der Offiziere Wilhelm Rudolph von Gall, Friedrich Wilhelm von Geismar, dessen Burschen (anonym), Jakob Heerwagen, Georg Paeusch sowie anderer Beteiligter Hanauer Geschichtsblätter, Band 41, Hanauer Geschichtsverein, Hanau 2005, . he commanded a regiment from Hanau under General John Burgoyne. Among the units sent to North America were one battalion of infantry, a battalion of jägers, a battalion of irregular infantry known as a Frei-Corps, and a company of artillery.

Brunswick-Wolfenbüttel

Brunswick-Lüneburg was a duchy that had been divided into several territories, one of which was ruled by George III as the Electorate of Brunswick-Lüneburg (Hanover). The neighboring Duchy of Brunswick-Wolfenbüttel (Brunswick) was ruled by Duke Charles I of Brunswick-Bevern; his son and heir, Charles William Ferdinand, was married to Princess Augusta of Great Britain, the sister of George III.

In 1775, Charles William Ferdinand ("Prince Carl") told King George III that Brunswick had soldiers who could be used to help put down the rebellion in the Americas. In December 1775, General Friedrich Adolf Riedesel began recruiting in anticipation of the finalized treaty. Brunswick was the first German-speaking state to sign a treaty supporting Great Britain, on 9 January 1776. It agreed to send 4,000 soldiers: four infantry regiments, one grenadier battalion, one dragoon regiment and one light infantry battalion. The Brunswick treaty provided that all troops would be paid in Imperial Thalers – including two months' advance pay, but required that all troops take an oath of service to King George III. A controversial clause in the agreement stipulated that Duke Charles I would be paid £7 and 4s to replace each Brunswick soldier killed in battle- with three wounded men equal to one dead man; Charles, however, would pay to replace any deserters or any soldier who fell sick with anything other than an "uncommon contagious malady."

Duke Charles I provided Great Britain with 4,000 foot soldiers and 350 heavy dragoons (dismounted)The heavy dragoons from Brunswick did not have horses and performed as foot soldiers. They were expected to acquire horses during the campaign, which led to the Battle of Bennington. under Lt-Colonel Friedrich Baum, all commanded by General Friedrich Adolf Riedesel.