There is a Derry Boro and Derry Station in Derry Twp., Westmoreland Co., also Derry Church in Derry Twp., Dauphin Co. also Derry Station in Madison Twp, Columbia Co. all in PA. There is a Dairy in Hanover Twp., Northampton Co. I have not heard of a Derry - Dairy in Armstrong Co. (for what its worth) Connie M.