The Fifteenth Michigan Infantry was organized at Monroe, left for Pittsburg Landing, March 27, 1862, arriving there April 5, participating in the battles of the sixth and seventh of the month, 32 killed, 4 wounded and seven prisoners taken. In repulsing the assault on Corinth, October 10^th, it lost 13 killed, 32 wounded and 5 prisoners.

From that point, the command proceeded to Grand Junction, November 19^th, to serve as garrison and provost guard. June 5, 1863, it was ordered to Vicksburg, Mississippi with the First Division, sixteenth corps to which it had been attached since the first of the year. Arriving at the mouth of the Yazoo, June 11, it proceeded up the river and disembarked at Haynes Bluff. Having been temporarily attached to the ninth corps, it participated with it in the advance on Jackson on the fourth of July. The Big Black river was crossed on the 6^th (this regiment leading) on rafts and swimming. On the twenty-third, it began its march back to the Big Black. It was here attached to the Second Brigade, fourth division, 15^th army corps, this corps having been ordered to reinforce the Army of the Cumberland, the regiment arriving at Memphis, October 8, and at Corinth, Mississippi on the 17^th. In the following days it proceeded to Iuka where it remained until October 25^th. November 1^st, it arrived at Florence, Alabama.

During 1863, the command lost 38 by death and 18 were taken prisoners. The command also re-enlisted during this year, were furloughed for a month, returned, served with distinction under Sherman throughout the Georgia campaign. It lost 18 killed, 18 died of disease and 79 wounded. In 1865 it served in the Carolina campaign and was discharged at Detroit, September 1, 1865.