Wilmington, Delaware, the state's largest city and the seat of New Castle County. It is on the Delaware River in the northern part of the state, about 25 miles (40 km) southwest of downtown Philadelphia, Pennsylvania.
Wilmington's most important industry is chemical manufacturing. It is headquarters of E. I. du Pont de Nemours & Company, one of the largest corporations in the United States. Wilmington is the commercial and financial center of Delaware and an Atlantic Ocean port. The New Castle County Airport and several expressways, including Interstate 95, serve the city.
Among Wilmington's many historical landmarks are Hendrickson House (1690), now a museum; Holy Trinity Church (1698), established by settlers from Sweden and commonly known as Old Swedes Church; and the Old Town Hall (1798), containing the museum of the state historical society. The Grand Opera House (1871) serves as Delaware's center for the performing arts. Contemporary works are featured at the Delaware Art Museum. At the Hagley Museum, a short distance north of Wilmington, are the original Du Pont gunpowder mills, industrial exhibits, and the home of Eleu-thère Irénée du Pont de Nemours, founder of the chemical firm. Nearby are two other former du Pont homes (now museums)—Winterthur and the Nemours Mansion. Both are immense and elegant, with exquisite gardens.
Led by Peter Minuit, a colony of Swedes built Fort Christina in 1638. Around it grew the village of Christinaham, future site of Wilmington. Christinaham was the capital of New Sweden, 1638–43 and again in 1654. The village was ruled by the Dutch from 1655 until it became an English possession in 1664. It was renamed Willington in 1731 and took its present name in 1739 when it was chartered as a borough. Wilmington was incorporated as a city in 1809 and has grown with the Du Pont Company, established here in 1802.