The monument to the 18th Pennsylvania Cavalry Regiment is south of Gettysburg on South Confederate Avenue. (39.78475° N, 77.2496° W; Google map; Monument map: Bushman Hill & Slyder Farm) It was dedicated in 1889 by the State of Pennsylvania.
The 18th Pennsylvania Cavalry Regiment was commanded at the Battle of Gettysburg by Lieutenant Colonel William Penn Brinton.
From the front of the monument:
18th Pennsylvania Cavalry
1st Brigade, 3d Division
Army of the Potomac
From the rear:
The Regiment participated in the cavalry fights at Hanover June 30th and Hunterstown July 2d 1863. On July 3d occupied this position, and in the afternoon charged with the brigade upon the enemy’s infantry behind the stone wall to the north of this point on the outer edge of the woods.
Present at Gettysburg 599 officers and men. Killed 2 men, wounded 4 men, captured or missing 8 men.
Mustered in August, December 1862. Consolidated with the 22d Pennsylvania Cavalry July 24th 1865, forming the 3d Provisional Pennsylvania Cavalry, which was mustered out October 31st, 1865.
Participated with the armies of the Potomac and Shenandoah in 51 battles, and out of a total enrollment of 2020, lost in killed, died, wounded and prisoners 668, of whom 131 died in the hands of the enemy while prisoners of war.
See more on the 18th Pennsylvania Volunteer Cavalry Regiment in the Civil War