The First Potomac Home Brigade was made up of four Companies. Company C known as the Keystone Rangers was mustered into service at Frederick, Maryland on September 9, 1861. When the organization was completed, these four companies were mustered into a battalion and Major Henry Cole was given command
of "Cole’s Cavalry".
The Keystone Rangers, consisting mostly men from the Emmitsburg and Gettysburg areas was commanded by Captain John Horner. Many of the men were farmers and tradesmen who were young, unmarried and were accustomed to the use of firearms. Most of the recruits of Horner’s Company even brought their own
horses. Their extensive knowledge of Western Maryland and the topography of the Shenandoah Valley that runs through Pennsylvania deep into southern Virginia, served as a great asset to the Union cause especially in the year of 1864.
During the winter of 1861, Cole’s Cavalry encamped along the Potomac River in Western Maryland. During General Thomas Jackson’s Romney Campaign in January of 1862, Cole’s Cavalry was among the meager defenders who held Hancock, Maryland, and checked Jackson’s advance until a stronger Federal force
Due to personal reasons with his health, Captain John Horner resigned his commission on June 2 of 1862, and Second Lieutenant Albert Hunter became Captain, commanding Company C.
In September of 1862, General Lee began his first invasion of Maryland. Cole’s Cavalry was ordered to Bolivar Heights near Harper’s Ferry when Confederate forces under General Stonewall Jackson surrounded Harper’s Ferry. On September 14th, it was apparent that the garrison was going to surrender.
Major Cole informed the commander, Colonel Miles, that he would not surrender his command. That night, Cole’s Cavalry with several other Cavalry Regiments crossed the Potomac River into Maryland, through the Confederate lines. While scouting near Antietam creek, Cole’s Cavalry captured a portion of Longstreet’s wagon train
and escorted it to Federal authorities in Chambersburg.
During the Gettysburg Campaign, Cole’s Cavalry fought many skirmishes and on June 28th, at Fountain Dale, Pennsylvania they captured artillerymen from Crenshaw’s Battery who were searching for fresh horses. Their most notable action during the Gettysburg Campaign was the burning of the pontoon bridge
on July 4th that General Lee had built across the Potomac, south of Hagerstown. This significantly delayed the Confederate retreat into Virginia.
On numerous occasions Cole’s Cavalry crossed swords with Mosby’s Rangers. On New Years Day of 1864, while Cole’s Cavalry was encamped at Loudon Heights, Colonel Mosby and his men attacked their camp without warning. Cole’s men, stumbling from their slumber came into a blazing fire fight and managed to
put up a defense that drove Mosby from their camp. In 1864 they fought next to General Sheridan during the Valley Campaign.
Cole’s Cavalry was mustered out of service on June 28, 1865 at Harper’s Ferry. It is estimated that the command rode over 7000 miles during its four years of service. Their exploits were among the most heroic and spectacular of any organization in the Eastern Theater of the Civil War.