Question: Westmoreland County, Pennsylvania is located west of a mountain range that runs for about how many miles?
Sentence (from "Allegheny Mountains"): The Allegheny Mountain Range , informally the Alleghenies and also spelled Alleghany and Allegany, is part of the vast Appalachian Mountain Range of the eastern United States and Canada and posed a significant barrier to land travel in less technologically advanced eras.
Relevant evidence: No