Camp Parapet was built within the current boundaries of Jefferson Parish when Carrollton was still the commercial center of the parish. Intended to help defend against both a naval and land attack, a jagged line of fortifications stretched from the river almost to the lake. In July of 1861, the plans were presented by Colonel Paul O. Hebert and Major M.L. Smith to the elderly Major General David Twiggs. Major General Mansfield Lovell soon succeeded Twiggs and named the structure "Fort John Morgan" after the young Kentuckian who sided with the Southern cause. The fortification was largely completed prior to the Union navy's advance up the river.
One of the Confederate units temporarily stationed there included Colonel Alfred Mouton's 18th Regiment of Louisiana Volunteers. This regiment and its commander later made a name for themselves in the 1864 Red River Campaign, playing a role in the Confederate victory at Mansfield.
As the federal fleet neared New Orleans, the Confederates in the area realized they were not well manned or supplied enough to repel the invasion and retreated north and west into other parts of the state. Unable to take the artillery with them, they spiked the guns or threw them in the river to keep them out of Union hands.
All that remains of Camp Parapet is the dirt and grass covered powder magazine near the river levee. It is located on Arlington Avenue, near that street's intersection with Causeway Boulevard. It is now listed on the National Register of Historic Places. Visiting the site in person, one should keep in mind it is in a residential neighborhood.