Armstrong

County, west-central Pennsylvania, U.S., bounded to the north by the Allegheny River and Redbank Creek and to the south by the Kiskiminetas River. It consists of a hilly region on the Allegheny Plateau, through which the Allegheny River has cut a deep valley roughly north-south in the western part of the county. Other waterways include Mahoning, Buffalo, and Crooked creeks,