The Battle of the Short Hills is also known as the Battle of Ash Swamp

On the 26th of June, 1777, Washington's Continental forces of under 6000 men fought a running battle on the plains below the Watchung Mountains with the combined British and Hessian troops numbering about 12,000. Early on that hot Thursday morning the British, under command of General William Howe, after feigning a departure from New Jersey suddenly at midnight began a march upon the "rebel" army that had left their mountain camp to come to the low country at Samp Town (South Plainfield), Quibble Town (Piscataway-North Plainfield), and outposts in The Short Hills and Ash Swamp (Scotch Plains) in order to watch the British.

In Howe's words, "the right under command of Lord Cornwallis, with Major General Grant, Brigadiers Matthew and Leslie and Colonel Donop took the route by Woodbridge towards Scotch Plains. The left, where I was, with Major Generals Stirn, Vaughan and Grey, Brigadiers Cleveland and Agnew, marched by Metuchen Meetinghouse to join the rear of the right column in the road from thence to Scotch Plains." A little before sunrise scouts of Colonel Daniel Morgan's riflemen encountered Cornwallis in Woodbridge (Green St./Rt. #1) and shots alerted Washington of the enemy's surprise approach. Discerning the British intent to secure the mountain passes, Washington began with haste to remove the main forces at Quibble Town and ordered the divisions of Greene, Lincoln, Stephen, and Sullivan back to the heights. The delaying tactics of the riffle men gave the American troops and local militia time to assemble.

The first massed resistance by American troops was on the crossroads at Oak Tree where Cornwallis' column was fired upon by a body of about 600 men under Brigadier General Thomas Conway at about eight a.m. His troops were joined by three companies of Pennsylvania-German volunteers of Major Nicholas Ottendorff, newly placed under the command of the French Colonel Charles Armand-Tuffin with three brass field pieces marking the first use of French command and arms in the war. After considerable fighting, Conway's troops, forced by the British through "Martin's Woods" (New Dover Rd., Edison), withdrew to join Stirling's main body at The Short Hills near Ash Swamp.

Lord Stirling, divided by Cornwallis, drew his troops into battle formation on rising ground near Ash Swamp determined to make a stand. His forces of 1,798 men included General William, "Scotch Willie", Maxwell's Brigade consisting of four New Jersey Regiments and Conway's and Armand's troops. In addition, they were joined by Morgan's and Dark's riflemen as well as an undetermined number of militia. The 3rd Hessian Grenadier battalion of von Minningerode attacked the rebels left flank and were joined by Howe's column.

Outnumbered by Howe's full forces with at least 15 cannons, the Americans stood their ground but the superiority of arms and numbers forced them to withdraw. Howe's aide Mueuchhausen in writing of the battle states; "General Lord Stirling who was in command had his horse shot and general Maxwell was alomost captured by the Hessian Grenadiers missing him only by a hair's breath...three new French brass three-pounders were taken."