The British had little time to debate the treaties, the Crown Forces had suffered large losses at the Battle of Bunker Hill and Boston was under siege. The Landgrave of Hessen would be required to have half of his units read to be inspected by Sir William Faucitt on the 14th of February and begin their march to the port of embarkation on the 15th. Beginning around February 29th, the First Division marched from their garrisons to the port of Bremerlehe with embarkation to England scheduled for 15-23 April. The fleet of 150 transports and frigates set sail from Portsmouth on the 6th of May for a long and uncomfortable voyage to America. At the same time the 8,000 Hessians troops of the First Division were enduring sickness and over crowding on the storm tossed Atlantic, units of the Second Division began their march towards the port of Bremerlehe.

The First Division would take part in the opening stages of the battle to control New York and it's harbor, a plan that was drafted in the early days of the war. If successful, it would give England a deep draft harbor and an important city to operate as the headquarters for future operation. The first operation of the taking of New York was Long Island on the 27th of August. The First Division, commanded by General von Heister and led by the Advanced Guard of von Wrede's Jägers and grenadiers from the Regiment von Donop, moved along the Flatbush Road as Howe moved up the right to flank the American line. This battle, the largest of the American Revolution, forced Washington to abandon Long Island and Brooklynn Heights on the 29th - 30th of August. The losses for the First Division during the battle were 2 killed and 26 wounded, one of the wounded being a Jäger, while they captured close to 1,100 prisoners.

The next step in General Howe's plan was to move on New York City, which he set in motion on the 15th of September. Landing at Kip's Bay, the First Division, with the Jägers of the Advanced Guard leading the attack, pushed their way south to the city while British Marines entered the city from the sea. The 16th of September found the English Light Infantry and 71st Highlanders taking heavy casualties in the Battle of Harlem Heights. The Jägers and Grenadiers of the Advanced Guard were called to assist the English units disengage from the battle.

Intent on flanking the heavily defended Harlem Heights, on 12 October Howe landed his force at Throgs Neck with one column moving on the Westchester bridge and the other on the Pelham road towards the ford. These columns found the bridge destroyed and both positions heavily defended. As a result, Howe established defensive positions and encamped. Seeing that Pell's Point may provide a tactical advantage, a force of mostly Hessian's lands at Pelham and pushes inland towards Eastchester along the Split Rock road against determined resistance. On the 20th Howe pushes on towards New Rochelle were he would encamp and wait for reinforcements expected to arrive from England.

The Second Division finally completed their voyage across the Atlantic when they rounded Sandy Hook and made land at Staten Island on 18 October. The troops were quickly unloaded and transferred by flat bottom boat to Manhattan Island, then moved through Westchester arriving at New Rochelle on 22 October. The first engagement of the 2nd Company with the Americans came on the 23rd when, while performing a reconnaissance of the area, the 2nd Company encountered a superior force of riflemen that pushed them back. The tide of the battle was turned when the Jägers were reinforced by the 71st Highlanders.