Mustered into service as a Captain on July 29th, 1861
Died 28 August 1862
Captain May was promoted to Major in February of 1862 and held that rank until the Battle of Brawner Farm on August the 28th where he was mortally wounded in the head.
It is believed that the Major was buried by Private Seth Peden and a Wisconsin soldier both of whom were killed in later battles. Isaac's grave location remains unknown.