Of 67 counties in the Keystone State, Armstrong County ranks 34th in terms of size (663 square miles). Armstrong County is in Pittsburgh & Countryside Pennsylvania. The total value of around 1,000 acres of ranches recently listed for sale in Armstrong County, Pennsylvania, was around $2 million. Browse all Armstrong County ranches for sale on the Land Network to find the ranch that's right for your business or commercial needs, from the sprawling legacy ranch to unbelievable residential ranch for your second home, investment property or retirement nest egg. The most common type of land for sale by combined acreage in Armstrong County is house.