Battle of Princeton

Background

Eight days after Trenton, Washington was back in New Jersey. Many of his men's enlistments ran out on 31 December; about 3,300 agreed to stay for a bounty of ten dollars. Intelligence was good. A young man, probably a student at the College of New Jersey, escaped from the British at Princeton on 30 December and reported some 5,000 British and Hessian troops there and no sentries on the east side of the town. Cadwalader drew a map of it, and Joseph Reed's scouts confirmed the back road that became the line of approach, the Saw Mill Road.

The British reacted quickly. Lord Cornwallis gathered more than 9,000 men at Princeton, left Lieutenant-Colonel Charles Mawhood's brigade there, and on 2 January marched on Trenton with about 8,000. A thaw had turned the road to mud, and American skirmishers slowed the column to little more than a mile an hour. By dusk Washington's roughly 6,000 men held the heights south of the Assunpink Creek, with the Delaware behind them. Three British attempts on the bridge failed, and Cornwallis put off the attack until morning.

That night a council of war decided not to retreat but to march round the British flank and strike Princeton, and perhaps the British depot and pay chest at New Brunswick. The baggage went to Burlington. About 500 men stayed behind to keep the fires burning, dig noisily and fire the odd gun. The temperature dropped and the mud froze hard, and the army slipped away by the Quaker Road towards the Saw Mill Road, twelve miles of back lanes in the dark.

The armies

Washington had about 4,500 men by the usual count; the 2010 mapping study by Robert Selig, Matthew Harris and Wade Catts reconstructs 5,600 to 5,800. They were the remnants of the 1776 Continental regiments from New England, Virginia and Pennsylvania, Edward Hand's Pennsylvania riflemen, the German Regiment, and John Cadwalader's 1,100 Philadelphia Associators, militia who had never fought a battle. Arthur St Clair's brigade, the Virginians and Daniel Hitchcock's New Englanders formed the lead division under John Sullivan. Hugh Mercer's brigade, a few hundred men, many with rifles that loaded slowly and took no bayonet, was among the weakest. The army had about 35 guns, but Selig reckons only about eight are known to have fired, among them Joseph Moulder's Philadelphia battery and Captain Neal's two New Jersey guns.

Mawhood's 4th Brigade was the British reserve: the 17th, 40th and 55th Regiments of Foot, a detachment of the 16th Light Dragoons, odd companies of grenadiers and light infantry, recruits and convalescents, and a Royal Artillery detachment; about 1,200 men by the usual count, about 1,500 in Selig's. They were regulars who trusted the bayonet against riflemen who had none, but they were outnumbered four or five to one and spread between the town and the road to Trenton.

The battle

The approach, night to about 7.15 a.m. The columns set off between about 10 p.m. and 2 a.m., in silence. A little before sunrise, at about 7.10 to 7.15, the head of the army reached a wood south of the Quaker meeting house near the Stony Brook, about two miles from Princeton and behind time. Washington split the army. Sullivan's division would wheel right along the Saw Mill Road and hit the town from the south and east. Two brigades under Mifflin and Hausegger would swing left up the Stony Brook, break the bridge on the Post Road and close the north side. Mercer and Cadwalader would follow Sullivan. The traditional account, from Washington's aide James Wilkinson, sends Mercer with about 350 men to the bridge; the mapping study argues it was Mifflin.

Discovery, about 7.45 a.m. Mawhood had orders to join Cornwallis at Trenton. He had crossed the Stony Brook with the 17th and part of the 55th, leaving the 40th in town, when his dragoons on Cochran's Hill saw the glint of arms: Sullivan's column, crossing his rear towards Princeton. He turned back. Washington, unsure what he faced, sent Mercer to deal with what he took to be a guard.

The orchard, about 8 a.m. This is the engagement CDB90 records as PRINCETON. Mercer's men reached the orchard of William Clarke's farm and drove back the dragoons skirmishing in front of it, who fired high. The 17th formed behind a fence at the end of the orchard, with two guns. After a few minutes of volleys at close range Mawhood ordered the bayonet. The riflemen could not stand it and broke. Mercer's horse was shot; he was knocked down, clubbed and bayoneted by men who reportedly thought he was Washington, and left for dead. Colonel John Haslet and Captain Neal were killed, and Neal's guns were turned on the Americans.

The crisis. Mercer's survivors ran back onto Cadwalader's militia as they came up past the Thomas Clarke house, and most of the Associators broke too. Moulder's guns on the rise kept firing grape and canister and gave the line something to form on. Washington rode up with the Virginia Continentals and Hand's riflemen, rallied the militia in person and led them forward to about 30 yards before ordering a volley. Both sides fired together. His aide John Fitzgerald is said to have covered his eyes; Washington emerged unhurt.

The rout, about 8.30 to 8.45 a.m. Hitchcock's New Englanders and Hand's riflemen lapped round both flanks. The 17th fell back to the ridge by William Clarke's house, then broke. The 55th, which should have charged with it, fell back on the town instead. About three-quarters of an hour after the first shots, by one American account, the regulars were in flight, leaving two brass field pieces. Mawhood and the survivors of the 17th cut their way out with the bayonet towards the Post Road and Trenton, with Americans in pursuit.

Frog Hollow and Nassau Hall. Sullivan's column pressed on to the edge of town. Men of the 40th and 55th lined the ravine of Frog Hollow below the college; two American regiments crossed it and they fell back into Nassau Hall. American guns fired on the building and 194 men surrendered. Others ran out of the front and escaped towards New Brunswick.

Aftermath

The Americans lost perhaps 25 to 44 killed and about 40 wounded; the British about 270 by Howe's return, killed, wounded and missing, and up to 450 or more by American counts. The 17th alone lost about 101 killed or wounded. Mercer lingered until 12 January and died in the Thomas Clarke house, tended by Benjamin Rush. A common grave by the battlefield colonnade is said to hold 15 Americans and 21 British.

The Americans held Princeton until the afternoon, while Cornwallis, hearing the guns, marched back from Trenton. A rearguard broke the Stony Brook bridge and held it while the army left by Kingston and the Millstone valley. Washington wanted to push on to New Brunswick and its £70,000 pay chest, but his men had gone two nights without sleep and his officers talked him out of it. He reached Somerset Courthouse that night, Pluckemin on the 5th and Morristown by the 6th. The British pulled back to New Brunswick and gave up most of their posts in New Jersey; months of skirmishing over forage followed.

The ten days from the Delaware crossing to Princeton are remembered as the turn of the war's first crisis, and Princeton as the Continental Army's first defeat of British regulars in the field. The 2010 mapping study moved the fighting closer to the town, onto land where the Institute for Advanced Study planned housing; a historian the Institute commissioned, Mark Peterson, called its route for the Saw Mill Road conjecture presented as fact.

Wargaming it

Princeton is a short, sharp meeting engagement with a lopsided total and an even fight where it mattered. About 4,500 to 5,800 Americans face 1,200 to 1,500 British, but at the orchard a few hundred of the 17th and the dragoons take on Mercer's riflemen and then Cadwalader's militia piecemeal. It suits a battalion or company game, turns of five to ten minutes, with the Clarke farms on one table and an optional second table for Frog Hollow and Nassau Hall.

The terrain is open farmland on a gentle ridge: the orchard and its fence, the two Clarke houses, the rise where Moulder's guns stood, Cochran's Hill and the Post Road, the Stony Brook and its bridge, the Frog Hollow ravine and the college. Frozen ground makes the going good.

Rules need to capture the bayonet against riflemen who have none, militia morale that can collapse and recover, and a commander who can rally troops in person at real risk. The British player must choose between fighting it out and breaking for Trenton; the American player has to feed in reserves before the line splits. What ifs: the 55th charges with the 17th, as a British officer thought it should have; the 40th comes out to support it; Mifflin's brigade closes the Post Road and traps Mawhood; Cornwallis marches faster and arrives while the Americans are still in the town.

Maps and pictures