WHITEMARSH, PENNSYLVANIA. 5-8 December 1777. George Washington kept his headquarters in Whitemarsh from 2 November to 10 December 1777 as the final struggle for control of the Delaware River played out. There, he began staff discussions to decide where to establish winter quarters. Before he could fall back or winter weather could prevent further action, Sir William Howe determined to make one more effort to bring his opponent to battle. But American intelligence reports kept Washington alert. For example, Mrs. Lydia Darragh (according to tradition) overheard British plans and sent word out of the city that a large British force would move during the night of 4-5 December to strike the American camp. As he so often did during the campaign, Howe marched in two columns, one primarily British and the other mostly German. Charles Lord Cornwallis's element marched directly along the Germantown Road. That movement was detected by Captain Allan McLane's outpost around 3 a.m. at Beggarstown (later Mount Airy), and the patrol immediately alerted Washington. British light infantry in Cornwallis's van kept going to Chestnut Hill and then halted there at dawn while the commanders pushed ahead to inspect the American positions.
Finding the Americans already deployed, Cornwallis opted for caution and waited at Chestnut Hill for Wilhelm Knyphausen to arrive with the other column. By midmorning Washington had sent out a strong combat patrol to obtain exact information on the enemy's size, location, and intentions. Brigadier General James Irvine, now leading Pennsylvania militia but formerly an experienced Continental officer, tangled with the light infantry for about twenty minutes. The militia withdrew after a wounded Irvine and about sixteen of his men had been captured. Howe spent the next two days cautiously probing but concluded that Washington's defenses were too strong and returned to Philadelphia. Although there were several more foraging operations by the British before the end of the year, the Whitemarsh probe marked the end of the campaign.
Howe's force probably approached ten thousand men; Washington most likely had slightly more men available. American losses seem to have been about forty, only six of whom were killed. British casualties were lighter, apparently amounting to one officer killed and a dozen men wounded on the 5th, although more men seem to have been picked off or to have deserted during the maneuvering.
Martin, David G. The Philadelphia Campaign: June 1777–July 1778. Conshohocken, Pa.: Combined Books, 1993.
revised by Robert K. Wright Jr.