Question: Valhalla is a hamlet and census-designated place (CDP) located within the town of Mount Pleasant, in Westchester County, is a county in the U.S. state of New York, it is the second-most populous county on the mainland of New York, after which location?
Sentence (from "Valhalla, New York"): The name of the community was inspired by a fan of the opera composer Richard Wagner, and the hamlet is known both for its location as the home of the primary hospital campus of Westchester Medical Center and New York Medical College, as well as burial places of the remains of numerous well-known people.
Relevant evidence: No