New Castle County, Delaware New Castle County Police and Emergency Medical Services Division Headquarters and the emergency communications center supporting 911 services. The present building opened in 2007 with a construction cost of . The Headquarters occupied a former elementary school building on the same site prior to erection of the current building. New Castle is a Democratic-leaning county. Because its population is almost double the combined population of Kent and Sussex, the winner in New Castle County has also won Delaware overall in each of the last seventeen presidential elections. In 1992, 2000, 2004 and 2016, the Republican candidate carried Kent and Sussex,
New Castle County, Delaware substantial majority of the state legislature, 27 state house districts and 17 state senate districts are based in the county. New Castle County, Delaware New Castle County is the northernmost of the three counties of the U.S. state of Delaware. As of the 2010 census, the population was 538,479, making it the most populous county in Delaware, with just under 60% of the state's population of 897,936 in the same census. The county seat is Wilmington. New Castle County is included in the Philadelphia-Camden-Wilmington, PA-NJ-DE-MD Metropolitan Statistical Area. The county is named after the English city of Newcastle. New Castle