: www.ci.wilmington.de.us Wilmington is the largest city in the state of Delaware, United States, and is located at the confluence of the Christina River and Brandywine Creek, near where the Christina flows into the Delaware River. It is the county seat of New Castle County and one of the major cities in the Delaware Valley metropolitan area. Wilmington was named by Proprietor Thomas Penn after his friend Spencer Compton, Earl of Wilmington, who was prime minister in the reign of George II of Great Britain. According to the 2010 census, the population of the city is 70,851, a decrease of 2.4% from 2000. The metropolitan area which includes the cities of Philadelphia, and Camden, New Jersey had a 2006 population of 5,826,742, and a combined statistical area of 6,398,896.