Battalion

In the U.S. Army a battalion has a headquarters and two to six companies, batteries or troops. In the Civil War most volunteers served in regiments, but some units were raised as separate battalions, as Illinois did among its 100-day troops in 1864.

In 20th-century records a battalion is normally a numbered part of a regiment, so a full unit reads like Company A, 1st Battalion, 116th Infantry Regiment. The records center in St. Louis asks for the full unit of assignment in that form when searching morning reports.