As noted before at vX, New Orleans exists because it was a portage site.
The Mississippi is long and winding – it’s nearly 100 miles from New Orleans to the Gulf of Mexico. Tough going for a sailing ship.
New Orleans is the point where the Gulf’s lagoons – Lake Ponchartrain and Lake Borgne – are closest to the river. In fact, small ships did sail right up Bayou St. John into what is now the heart of the city.
Now there’s a paper looking at how portage sites are still leading to local increasing returns to scale:
A new NBER paper got me thinking about the same thing in a surprising context: river portages. I think this stuff is riveting. [-]
Portage: Path Dependence and Increasing Returns in U.S. History
Hoyt Bleakley, Jeffrey Lin
We examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the fall line, a geomorphologic feature in the southeastern U.S. marking the final rapids on rivers before the ocean. Historically, waterborne transport of goods required portage around the falls at these points, while some falls provided water power during early industrialization. These factors attracted commerce and manufacturing. Although these original advantages have long since been made obsolete, we document the continuing—and even increasing—importance of these portage sites over time. We interpret this finding in a model with path dependence arising from local increasing returns to scale.
Of course, I grew up in the Buffalo suburbs, and Buffalo is the end point of one of the biggest portage avoidances in the world: how to get from New York City to the Great Lakes.