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) Lieutenant colonel (United States) In the United States Army, U.S. Marine Corps, and U.S. Air Force, a lieutenant colonel is a field-grade military officer rank just above the rank of major and just below the rank of colonel. It is equivalent to the naval rank of commander in the other uniformed services. The pay grade for the rank of lieutenant colonel is O-5. In the United States armed forces, the insignia for the rank consists of a silver oak leaf, with slight stylized differences between the Army/Air Force version and the Navy/Marine Corps version. Promotion to lieutenant colonel is governed