Pari gbolohun yii: Cowdin jẹ ọgagun ti 2nd Massachusetts Militia Regiment ni ibẹrẹ ogun, ati pe a yan ọgagun ti 1st Massachusetts Infantry ni Oṣu Karun ọjọ 25, ọdun 1861. O ṣe olori ẹgbẹ rẹ ni ogun ti Blackburn's Ford ni Oṣu Keje ọjọ 18, ọdun 1861, o jẹ apakan ti Israel B. Richardson's brigade ti Daniel Tyler's Division ni Ogun akọkọ ti Bull Run, nibiti a ti pa ẹṣin rẹ. Ó tún rí ìṣẹ̀lẹ̀ ní Williamsburg,
Fair Oaks, Glendale, Malvern Hill àti Chantilly.