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 "Scotts Corners, New York"): As of the 2010 census, the CDP population was 711, making Scotts Corners Westchester County's smallest census-recognized area.
Relevant evidence: No