New Castle is a city in Henry County, Indiana, east-northeast of Indianapolis, on the Big Blue River. The city is the county seat of Henry County. New Castle is home to New Castle Fieldhouse, the largest high school gymnasium in the world. The city is surrounded by agricultural land. In the past, it was a manufacturing center for the production of sheet iron and steel, automobiles, caskets, clothing, scales, bridges, pianos, furniture, handles, shovels, lathes, bricks, and flour. Starting in the early 20th century, it was known as the Rose City, at one point having 100 florists and numerous growers.<ref>Herbert L. Heller, Historic Henry County, vol. 3: 1880-early 1940s), pp. 329-331.</ref> According to the 2010 census, the population was 17,396. New Castle Correctional Facility, with a capacity of over 3,500 inmates, is located just north of the city. History New Castle was platted in 1823, and named after New Castle, Kentucky. A post office was established at New Castle in 1823. The Maxwell automobile factory, later owned and operated by Chrysler Motor Corp. was, at the time of construction (1907), the largest automotive manufacturing plant in the nation. The Chrysler Enclosure, Gen. William Grose House, Henry County Courthouse, and New Castle Commercial Historic District are listed on the National Register of Historic Places. Geography New Castle is located at . According to the 2010 census, New Castle has a total area of , of which (or 99.71%) is land and (or 0.29%) is water. Government New Castle is a third class city and has a seven-member city council chaired by the mayor. One council member is elected from each of the city's five districts and two are elected at-large. The clerk-treasurer and city judge are also elected offices. City elections are held every four years in the year preceding presidential elections. The mayor is elected by popular vote and appoints the police chief, fire chief, city attorney, and department heads of the various municipal agencies. List of mayors of New Castle, Indiana Demographics 2020 Census As of the census of 2020, there were 17,396 people, 6,951 households, and 2,701 families living in the town. The population density was . There were 8,606 housing units at an average density of . The racial makeup of the county was 92.1% White, 1.8% African American, 0.5% Asian, 0.03% Native Hawaiian or Pacific Islander, 0.2% Native American or Alaska Native, 0.1% from other races,