New Orleans doesn’t exist without Bayou St. John.
Of course, the stretch of land that is now our home was discovered, and first settled, via the Mississippi River. But, holy moly, does that river bend and turn and weave.
Not so bad if you’re in a ship that’s steam-powered, or motor-powered, or whatever kind of power people use now. But if you were sailing, those bends were a giant pain in the ass. You need the wind. So you wait for it — maybe for several days — to get you going in the direction you want. You go a few miles. And then the river abruptly changes direction. So you wait, again, for the wind to change — maybe another couple of days — to go a few miles more.

Because of this, when local American Indians showed the French there was a straighter shot to the city directly from the Gulf of Mexico, via Lake Borgne, Lake Pontchartrain, and Bayou St. John, this became the preferred route.