Raised in the Harrisburg area and the Coal Region in August and September 1864, the regiment was sent to the Manassas Gap Railroad to guard it against the attacks of Confederate partisan rangers led by John Mosby.

The 202nd Pennsylvania was raised in the Harrisburg area and the Coal Region beginning in early August 1864 for a one-year term in response to President Abraham Lincoln's call for 500,000 men.

The vital Manassas Gap Railroad transported supplies to the Army of the Shenandoah, and as a result was frequently attacked by Confederate partisan rangers led by John Mosby.

[3] The regiment fought in skirmishes against the Mosby men at Salem on 8 and 16 October,[4] suffering several casualties although inflicting losses on and driving off the Confederate forces.

A train was derailed while moving at full speed by the guerrillas on 10 October, killing four to five and severely wounding an estimated twenty, after which they fired upon the survivors.