At the outbreak of the U. S. Civil War, Anderson Bowman enlisted as a Private in the 3rd Regiment, Missouri Volunteer Infantry, Company D, on November 19, 1861, in Pittsfield, Illinois, the Pike County seat. For the rest of 1861 the Regiment, part of the Army of Southwest Missouri, skirmished in southern Missouri and eastern Arkansas under General Samuel R. Curtis. Then in February, 1862, the Army engaged in its greatest battle of the war, at Pea Ridge, Arkansas, and then marched on to Helena, Arkansas, occupying the city. It was during this period that Anderson Bowman, on September 27, 1863, died of typhoid fever aboard the hospital boat Metripolitan (sic?) which lay off Helena, Arkansas, on the Mississippi River. (He was 39, not 35, as reported in the Union Army records.)
In total the Regiment lost in service over the course of the War three officers and 89 enlisted men killed or mortally wounded and three officers and 145 enlisted men by disease.