Crawford only had two brigades of the Pennsylvania Reserves with him at Gettysburg. The other brigade was located in the D.C. Garrison.

Present:

3rd Division, 5th Army Corps (Blue Maltese Cross)
Brigadier General Samuel W. Crawford

First Brigade, Colonel William McCandless
1st Pennsylvania Reserves (also known as 30th Pennsylvania Infantry)
2nd Pennsylvania Reserves
6th Pennsylvania Reserves
13th Pennsylvania Reserves ("Bucktails")

Third Brigade, Colonel Joseph W. Fisher
5th Pennsylvania Reserves
9th Pennsylvania Reserves
10th Pennsylvania Reserves
11th Pennsylvania Reserves
12th Pennsylvania Reserves.

These two brigades charged from the north slope of Little Round Top, through Plum Run, and into the Wheatfield, at twilight on July 2nd. Their charge broke the final Confederate offensive spirit, and was the last significant or substantial fighting on the Federal left on July 2nd.

THe Second Brigade, with D.C. Garrison, consisted of:

3rd Pennsylvania Reserves
4th Pennsylvania Reserves
7th Pennsylvania Reserves
8th Pennsylvania Reserves

I'm not sure who commanded this brigade at D.C.

Company K, of the 1st Reserves, was from Gettysburg, "The Boys Who Came Home to Fight". General Crawford was from Franklin County (Chambersburg), so he was also fighting for his home town.