Patterson's Independent Kentucky Company of Engineers & Mechanics was organized at Camp Haskin near Somerset KY and mustered into service on 25 Sep 1861 under the command of Captain William F. Patterson. The unit was also known as the "Pioneer Corps" or "KY Pioneer Infantry".The regiment served unattached, Army of the Ohio, to March 1862. Engineers, 7th Division, Army of the Ohio, to October 1862. Cumberland Division, District of West Virginia, Department of the Ohio, to November 1862. 9th Division, Right Wing, XIII Corps (Old), Department of the Tennessee, to December 1862. Unattached, Sherman's Yazoo Expedition, to January 1863. Unattached, 9th Division, XIII Corps, to July 1863. Unattached, XIII Corps, Army of the Tennessee and Department of the Gulf, to October 1863. Unattached, XIII Corps, Texas, to July 1864. Engineer Brigade, Department of the Gulf, to January 1865.Patterson's Company mustered out of service at Louisville KY on January 22, 1865.