Short Hill rises sharply from the Piedmont countryside of the Loudoun Valley, northwest of Purcellville.

North of the gap, the ridge quickly achieves heights of greater than 600 feet (180 m), and continues for 12 miles (19 km), gradually gaining elevation, before dropping precipitously to the Potomac River.

The rocks were originally deposited contiguous with those of the Blue Ridge Mountains and uplifted together during the Grenville Orogeny.

The two ridges were later separated in the late Paleozoic era by movement along the Short Hill Fault, which runs along the western edge of the mountain.

[2] Short Hill Mountain north of Hillsboro is home to one of several AT&T Corporation Project Offices, underground facilities constructed in the 1960s to provide redundant communications services.