lets take a look at Wilmington, one of the best deep water ports along the east coast through much of the united states history. massive shipbuilding hub during ww2, over 240 ships built there. still a huge international shipping destination today.
Killitquick already did it.
Also, as Wishy Washy said it includes suburbs 3 feet from the downtown of other cities, so it's obviously not the total urban area.