Armstrong, IndianaArmstrong is an unincorporated community in Armstrong [Township, Vanderburgh County, Indiana|Armstrong Township], Vanderburgh [County, Indiana|Vanderburgh County], in the U.S. state of Indiana.HistoryA post office was established at Armstrong in 1856, and remained in operation until it was discontinued in 1957.GeographyArmstrong is located on Indiana [State Road 65] west-northwest of Darmstadt.