The 148th Pennsylvania Infantry served as a member of Cross’ Brigade in Caldwell’s Division of the Second Corps, Army of the Potomac, a Fighting 300 Regiment. The unit was commanded by Colonel Henry Boyd McKeen (1835-1864). McKeen was a local fellow, being a lumber merchant in Camden, New Jersey. At the Battle of Gettysburg, he led his regiment in action in the Wheatfield and Rose Woods on the second day of Battle. When his brigade commander, Col. Edward Cross of the 5th New Hampshire Volunteer Infantry, was mortally wounded in the Rose Woods, he assumed command of the brigade, which he commanded through the rest of the Battle. He remained in command of the brigade (which was the 1st Brigade, 1st Division, II Corps, Army of the Potomac) though the Mine Run Campaign, and the Battles of the Wilderness, Spotsylvania and Cold Harbor. At Cold Harbor, he led his brigade in the fruitless and bloody Union frontal assault on impregnable Confederate positions, and was killed at the head of his command. Today his name is inscribed on the 81st Pennsylvania Monument in the Wheatfield, and on the 1st Brigade, 1st Division, II Corps Marker on Ayres Avenue in the Rose Grove in the Gettysburg National Military Park.
The 148th Pennsylvania Infantry Position Marker is located on the left or west side of South Hancock Avenue if traveling north. The Pennsylvania State Monument looms large and is due north not too far away. Directly across from the monument is the Caldwell's Division Tablet (MN429). 
Parking is available along Hancock Avenue at enlarged shoulder cutouts on the side of the road, directly across from the other various monuments. The best parking is on Humphreys Avenue at a dedicated parking lot across from the Pennsylvania Monument. Be sure to keep vehicles off the grass or you will be ticketed by park police. I visited this monument on Thursday, July 5, 2012 in the later part of the afternoon. I was at an elevation of 575 feet, ASL. I used a Canon PowerShot 14.1 Megapixel, SX210 IS digital camera for the photos.
While the marker does not qualify for individual contributing status, this monument, along with one other position markers and two flank markers does assist with the primary monument in its contributing status. This position marker and the 148th Pennsylvania Infantry Monument collectively are contributing features to the Gettysburg National Military Park Historic District which is nationally significant under NR Criteria A, B, C & D. Areas of Significance: Military, Politics/Government, Landscape Architecture, Conservation, Archeology-Historic. Period of Significance: 1863-1938. The original National Register Nomination was approved by the Keeper March 19, 1975. An update to this nomination was approved by the Keeper on January 23, 2004. The monument is identified as structure number MN139-C.
The monument was erected by the Commonwealth of Pennsylvania in 1901. The monument denotes the regimental location on July 3, 1863. It is composed of a roughly hewn granite featuring the Second Corps trefoil on the front face. The marker is positioned close to the road. The position marker is referenced and described a few times in the NRHP narrative for the primary monument. The parts concerning this monument have red font to make it easier to find.
The brief inscription on the front face of the marker reads as follows:
148th Regiment
Pennsylvania Infantry
1st Brigade. 1st Division. 2nd Corps
Occupied this position July 3 1863
From the Nomination Form:
Marks position of 148th Pennsylvania Infantry on afternoon of July 2, 1863. 1 of 110 mns in Park to PA commands at Gettysburg. Located in Wheatfield, W of Ayres Ave. Pos. marker (1901) marks position of regiment on July 3, 1863, located W of Hancock Ave.
Short Physical Description:
Mn, 2 flank markers & 1 position marker. 2 course base, 6'2"x6'3". Shaft 4'7" sq., inscription & corner panels, w/ cross-gable cap & infantry accoutrements. All 14'3" H. Flank markers: rough bases 4'11"x2'10"; shafts w/ trefoil top, 4'1"x2'3". All 6'3" high
Long Physical Description:
N/A
My Sources
1.
NRHP Nomination Form
2.
SIRIS
3.
Stone Sentinels
4.
Virtual Gettysburg
5.
Draw the Sword
6.
Historical Marker Database
7.
Wikipedia
8.
Find A Grave