David Irwin listed in Chester County, Pennsylvania as Private in Captain Robert Cochran’s Return for the year 1787. Colonel Speers Battalion, Male, White Inhabitants.
David Irwin listed as Ensign in A Return of Militia Officers of the County of Westmoreland, Pennsylvania, 3rd Battalion under command of Colonel Abraham Hendricks and Lieutenant Colonel Christopher Truby – Agreeable to the different election July 7, 1789.
David Irwin listed as Lieutenant in Return of the Commissioned Officers of the Battalion of Militia in Westmoreland County commanded by A. Tannehill Lieut. Colonel on July 10, 1788.
David Irwin listed as Lieutenant in 4th Battalion, 8th Company under the command of Captain Abdiel McClure in “A Return of the Commissions of the Officers of the four Battalions of Militia in the County of Allegheny, Tuesday, May 1, 1792.”
David Irwin held an election at his home for the appointment of the 1st and 2nd Lieutenants in the first Light Infantry Company of a 1st Regiment of the militia of the City of Philadelphia, held September 15, 1794. The following persons were chosen, Lieutenant Robert McClintick and Lieutenant Sam Lees. The note was signed by Lewis Nicolas.