Archaeological investigations have discovered that the fort location was a site of the Pre-Columbian Marksville culture dating back to circa 300 CE, with continued occupation afterwards.

The first small fort here was erected by the French in 1701, before the founding of the city of New Orleans, to protect the important trade route along Bayou St. John.

After Louisiana passed to Spanish control, a larger brick fort was constructed at the site of the neglected old French fortification; this was known as San Juan del Bayou.

It featured restaurants, a casino, a resort hotel, dancing pavilions, an alligator pond, and in its later decades amusement rides such as the "Scenic railway", a roller coaster.

[6] The site of Spanish Fort, mostly a brick ruin, can still be seen along the upper side of the Bayou just back from Allen Toussaint Boulevard, adjacent to what is now the "Floral Park" section of the Lake Vista neighborhood.