William Firey; C was recruited primarily from Emmitsburg, Maryland and Gettysburg, Pennsylvania and was commanded by Capt.

John Horner; and D was made-up of men mostly from Baltimore City and Howard County, Maryland, and was commanded by Capt.

Company B served, through March 1863, independent of the battalion, mostly in West Virginia, western Maryland, and the northern part of the Shenandoah Valley.

For the balance of the year, through early 1863, the company operated along the Chesapeake and Ohio Canal and around Martinsburg, West Virginia.

During the escape from Harpers Ferry, Cole's Battalion encountered and captured Confederate Gen. James Longstreet's ammunition train at Sharpsburg, Maryland, on September 15.

Stuart in his raid into Pennsylvania and engaged portions of the Confederate cavalry force at Hyattstown, Md.

In the dark morning hours and freezing cold temperatures of January 10, 1864, Mosby attempted to make an attack upon the camp of Cole's Battalion at the Battle of Loudoun Heights and was soundly defeated in the effort.

The battalion was increased to a full regiment with the action of eight new companies, E, F, G, H, I, K, L, and M. Organized at Baltimore and Frederick from February 9 to April 23, 1864, elements of the new regiment participated in Gen. Franz Sigel's expedition from Martinsburg, W. Va., to New Market, Va., on April 30-May 16, and saw action at the Battle of New Market, May 13–15.

Following the defeat of Jubal Early in the Shenandoah Valley, Cole's Regiment served on duty in West Virginia, operating against Mosby and guarding Baltimore & Ohio Railroad until June, 1865.