where is middletown delaware
Middletown, DE. Sponsored Topics. Middletown is a town in New Castle County, Delaware, United States. According to the 2010 Census, the population of the town is 18,871. Middletown is located at 39Â°27â²16â³N 75Â°42â²50â³W / 39.45444Â°N 75.71389Â°W / 39.45444; -75.71389 (39.454352, -75.713816) with an elevation of 69 feet (21.0 m).