The Twenty-sixth was one of the first regiments that marched to the defense of the national capital. Organized in Philadelphia April 20, 1861, the regiment was in company with the Sixth Massachusetts and Twenty-seventh Pennsylvania when it was attacked by a mob while passing through Baltimore, on April 19, 1861, in which affair the regiment lost one man killed and several wounded. The regiment was not mustered-in until May 5th, when it was sworn in for three years; the enrollment, however, included very few of the original command who were at Baltimore, as they had tendered their services for a short term only. The 26th had the distinction of being Pennsylvania's first three year regiment.
The regiment lost during service 6 Officers and 143 Enlisted men killed and mortally wounded and 2 Officers and 71 Enlisted men by disease.