Foley Branch (Bull Run tributary)Foley Branch is a long first-order tributary to Bull Run in Loudoun County, Virginia.CourseFoley Branch rises on the South Fork Broad Run divide about 2.25 miles northeast of Catharpin, Virginia and then flows south to join Bull Run about 2.5 miles northeast of Arcola, Virginia.WatershedMassey Creek drains of area, receives about 47.1 in/year of precipitation, and is about 24.64% forested.