Wilmington, Delaware - Geography

Geography

According to the United States Census Bureau, the city has a total area of 17.0 square miles (44 km2). Of that, 10.9 square miles (28 km2) is land and 6.2 square miles (16 km2) is water. The total area is 36.25% water.

The city is located at the confluence of the Christina River and the Delaware River, approximately 25 miles (40 km) southwest of Philadelphia, Pennsylvania. Wilmington Train Station is one of the last stops on Philadelphia's SEPTA rail transportation system and is also served by Northeast Corridor Amtrak passenger trains. Wilmington is also one of the major cities served by I-95, although the twin-span Delaware Memorial Bridge, a few miles south of the city, provides direct highway access between Delaware and New Jersey, carrying the I-295 eastern bypass route around Wilmington and Philadelphia, as well as highway U.S. 40, which continues eastward to Atlantic City, New Jersey.

These transportation links and geographic proximity give Wilmington some of the characteristics of a satellite city to Philadelphia, but Wilmington's long history as the most important city in Delaware, its significant urban core, and its independent value as a business destination makes it more properly considered a small but independent city in the Philadelphia metropolitan area.

Wilmington lies along the Fall Line geological transition from the Mid-Atlantic Piedmont Plateau to the Atlantic Coastal Plain. East of Market Street, and along both sides of the Christina River, the Coastal Plain land is flat, low-lying, and in places marshy. The Delaware River here is an estuary at sea level (with twice-daily high and low tides), providing sea-level access for ocean-going ships.

On the western side of Market Street, the Piedmont topography is rocky and hilly, rising to a point that marks the watershed between the Brandywine River and the Christina River. This watershed line runs along Delaware Avenue westward from 10th Street and Market Street.

These contrasting topography and soil conditions affected the industrial and residential development patterns within the city. The hilly west side was more attractive for the original residential areas, offering springs and sites for mills, better air quality, and fewer mosquitoes.