That is another thing that the Great Lakes Cities (In the American side) have in common. They are extremely centralized at the coast and expand from there.
DSC_1146.jpg by
Giles Moger, on Flickr
Cleveland, OH by
Anomalous_A, on Flickr
Detroit by
Chris Parfeniuk, on Flickr
And yeah, I know most American cities are centralized like this, but this is more apparent here. Only the Northeastern cities are this centralized as a group. Many Sunbelt cities have more than one node and there is considerable distance between them.