I wasn't actually thinking of the Wicomico on the Eastern Shore when I read about Great Shoals, but about the Wicomico in Virginia which does flow into the Bay and not the Potomac. Of course that one is technically called the Great Wicomico. And the Little Wicomico is just north of it. I don't usually bother with the adjectives, and just say Wicomico since the Great Wicomico is the one that I've been to and fairly often.

Since the (Great) Wicomico is the one that I use the most, I tend to regard the other three as minor rivers.

It's almost as confusing as Back Creek/River or Mill Creek