The Battle of Cooch's Bridge, also known as the Battle of Iron Hill, was fought on September 3, 1777, between the Continental Army and American militia and primarily German soldiers serving alongside the British Army during the American Revolutionary War. It was the only significant military action during the war on the soil of Delaware, and it took place about a week before the major Battle of Brandywine. On August 25, Howe's army disembarked below a small town called Head of Elk (now known as Elkton, and located at the head of navigation of the Elk River) in Maryland, about 50 miles south of Philadelphia. Due to the relatively poor quality of the landing area, his troops moved immediately to the north, reaching Head of Elk itself on August 28. Advance troops consisting of British light infantry and German Jäger moved east across Elk Creek and occupied Gray's Hill, about one mile west of Iron Hill, near Cooch's Bridge, which was a few miles south of Newark. The bridge was named for Thomas Cooch, a local landowner whose house was near the bridge. General George Washington would normally have assigned the duties of advance guard to Colonel Daniel Morgan and his riflemen, but he had detached these to assist Major General Horatio Gates in the defense of the Hudson River Valley against the advance of Lieutenant General John Burgoyne.

Since they were unavailable, he organized a light infantry corps consisting of 700 picked men from Continental Army regiments and about 1,000 Pennsylvania and Delaware militia, and placed them under the command of Brigadier General William Maxwell. These troops occupied Iron Hill and Cooch's Bridge. A small company of Hessian dragoons led by Captain Johann Ewald headed up the road from the tavern toward Cooch's Bridge as Cornwallis's advance guard. These were struck by a volley of fire from an American ambush and many of them fell, either killed or wounded. The battle lasted for much of the day; at Cooch's Bridge, Maxwell's men made a stand until they "had shot themselves out of ammunition" and "the fight was carried on with the sword" and bayonet. After seven hours of fighting, the Americans were forced to retreat from Iron Hill across Cooch's Bridge, taking up a position on the far side. While the 1st Battalion under Robert Abercromby became mired in swampy terrain attempting to ford the Christina River, the 2nd Battalion reached the right of the Jäger and the bridge was taken. Maxwell's army then retreated back toward Wilmington. Cornwallis occupied the house of Thomas Cooch, and Howe's forces remained at Iron Hill for five days.