Original photo: Civilwar.org
Save for the Union's aborted "Mud March," the winter of 1863 saw Confederate and federal forces idle in their camps until roads became passable and the frigid weather abated. But fighting at the battle of Kelly's Ford in Virginia broke out on March 17, 1863, ending the monotony of winter camp for the two sides.
For the first time, Union forces were able to mass a formidable cavalry force for an attack. All told, some 2,100 troopers in the Union cavalry division moved on Confederate positions, aiming to do battle near Culpeper, not far from the ford. But when Confederates detected Union movements, fighting erupted instead near the ford where the Southerners had taken up positions behind felled trees and other obstacles. The bitter combat raged until Confederate cavalry troops successfully counterattacked, prompting Union forces to withdraw by mid-afternoon of that March 17th. The outcome appeared inconclusive.
Nonetheless, the Union's cavalry — which had only recently been united from far-flung units by the U.S. War Department — proved itself to be a formidable fighting force that would be used to greater effect later in the war, including an appearance at the Battle of Gettysburg.