High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Vienna Township is one of the twenty-four townships of Trumbull County, Ohio, United States. The 2000 census found 4,021 people in the township, 3,993 of whom lived in the unincorporated portions of the township. Part of the city of Girard is located in southwestern Vienna Township, and the census-designated place of Vienna Center is located in the township's north.