Under the command of Brig. Gen. Lovell Rousseau, the 30th Indiana was led by Colonel Sion Bass. On 7 April 1862, the second day of the battle, Bass was mortally wounded and Pvt. Mawhorter himself suffered a wound to the left leg in fighting near Water Oaks Pond. The wound left him unfit for military duty in the field. He transferred to the Veteran Reserve Corps and finally mustered out of the service in November 1864.