Sewickley Township, Westmoreland County, Pennsylvania  Sewickley Township is a township in Westmoreland County, Pennsylvania, United States. The population was 5,996 at the 2010 census. The Bells Mills Covered Bridge was listed on the National Register of Historic Places in 1980. According to the United States Census Bureau, the township has a total area of 26.8 square miles (69.5 km²), of which, 26.6 square miles (68.9 km²) of it is land and 0.2 square miles (0.5 km²) of it (0.75%) is water. Sewickley Township has five land borders, including North Huntingdon Township to the north, Hempfield Township to the east and southeast, Madison borough to the east-southeast, South Huntingdon Township to the south, and Sutersville borough to the southwest. Across the Youghiogheny River in Allegheny County to the west, Sewickley Township runs adjacent with Elizabeth Township. The CDP, Herminie, also resides within the township. At the 2010 census there were 5,996 people, 2,524 households, and 1,722 families living in the township. The population density was 225.4 people per square mile (87.0/km²). There were 2,766 housing units at an average density of 104.0/sq mi (40.1/km²). The racial makeup of the township was 98.46% White, 0.37% African American, 0.31% Asian, 0.11% from other races, and 0.77% from two or more races. Hispanic or Latino of any race were 0.66%. Of the 2,524 households 24.5% had children under the age of 18 living with them, 53.0% were married couples living together, 10.2% had a female householder with no husband present, and 31.8% were non-families. 27.4% of households were one person and 12.2% were one person aged 65 or older. The average household size was 2.37 and the average family size was 2.88. The age distribution was 19.9% under the age of 18, 5.1% from 20 to 24, 22.6% from 25 to 44, 32.2% from 45 to 64, and 17.9% 65 or older. The median age was 45 years.