Armstrong

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, as well as Keystone, Mahoning Creek, and Crooked Creek lakes. The county, created in...