Armstrong County, Pennsylvania is located in the western central portion of the state. It is surrounded by Clarion County to the north, Jefferson and Indiana Counties in the east, Westmoreland County to the south, and Butler County to the west.
According to a September, 2009 report, Marcellus shale drilling had been fairly active in the county. There had been 26 Marcellus wells drilled to date with six of these having been horizontal ones. The wells are concentrated in the central and southern part of the county. Snyder Brothers Inc. had drilled along Rt. 422 near near Worthington. A vertical well had been drilled near the Clarion County line in Redbank Township by Petroleum Development.
EQT Corp. holds 34,000 acres in Armstrong County with a high net revenue interest. It had drilled one well there in the third quarter of 2010 with initial 24-hour production of 15 Mmcfe/d.