Brush Run is a long 2nd order tributary to Jacobs Creek in Westmoreland County, Pennsylvania.
According to the Geographic Names Information System, it has also been known historically as:
Brush Run rises about 1 mile east of Kecksburg, Pennsylvania, and then flows southwest to join Jacobs Creek about 0.5 miles southeast of Mount Pleasant.
Brush Run drains of area, receives about 43.4 in/year of precipitation, has a wetness index of 403.86, and is about 36% forested.