History of the Office of The Inspector General of the United States Army (IG January 10, 1863April 1, 1864; January 2, 1881March 8, 1885) was assigned as the "de facto" head of the Office of the Inspector General, which, until then had not existed. 2 major generals, 7 brigadier generals, 18 colonels, 118 lieutenant colonels, and 149 majors of the regular army served inspector duty during the Civil War. On January 22, 1866, a War Department order established the duties of the inspector general as: In July 1866, the number of inspectors general with the rank of colonel was fixed at four; assistant inspectors general with the rank of lieutenant colonel at three;
Lieutenant colonel (United States) case with George A. Custer, who was a lieutenant colonel in the regular army, but held the brevet rank of major general. The 20th century saw lieutenant colonel in its present-day status although, during the 1930s, many officers again found the rank to be terminal as the rank of colonel was reserved for only a select few officers. In the United States Army and the United States Marine Corps (USMC), a lieutenant colonel typically commands a battalion/squadron-sized unit (300 to 1,200 Soldiers/Marines), with a major as executive officer (XO) and a command sergeant major/sergeant major (USMC) as principal NCO or