continental divide(s)

On the way to Wisp, you pass a sign claiming you are passing the "Eastern Continental Divide." While a harmless sign to most, it spurred quite the debate in the car. And by debate, I mean I ranted about it while the others shook their heads and Lelaine called me a moron.

I do not believe the eastern continental divide exists. Our continent is bordered by two oceans. That means that the true continental divide is the one in which water on one side flows to the Pacific and the other side the Atlantic. The "eastern continental divide" apparently exists because water to the east flows to the Atlantic and to the west the Mississippi River. But where does the Mississippi go? Into the Gulf of Mexico, which then feeds into the Atlantic. So water on both sides of the "eastern continental divide" ends up in the same place. In other words, it isn't a continental divide.

Aren't you as outraged by this as I am? I will assume the lack of comments means that you are so worked up you cannot type a response.