Prior to colonization, Llanerch was land belonging to the Lenape tribe, and fell under possession of William Penn by royal charter. where it was subsequently settled by Welsh Quakers.[3] Much of the Welsh influence on the area today is pertinent through road names such as "Llandillo", "Llandaff", and "Bewley". The name of Llanerch itself derives from a now-abolished Welsh commote, presumably where settlers of the region came from.[4]
Until the 1890s, Llanerch remained a mostly undeveloped area, with only a handful of families occupying in the area.[5] However, following the development of railway in nearby Philadelphia, Llanerch's population grew as the area became a junction between the city and many smaller, nearby boroughs. "The Battle of Llanerch Crossing" (1895) was a rights battle over land between railway companies that ended at a crossroads in Llanerch, ending with a ruling at the Pennsylvania Supreme Court.[6][7] There is a memorial to the historical background involving the case in the form of Llanerch Crossing, a small park with a mural and markers detailing the history of the feud.[8]
The community is home to the historic Llanerch Presbyterian Church, built in 1912,[10] and the former St. Andrew's Brookline Methodist Church, built in 1898, no longer in commercial use.[11]