In the summer of 1862, the 3rd Lemoyne Regiment of Confederates was holed up in the area, preparing to ambush any federal troops that planned to take Saint Denis via the Lannahechee. The food was rotten and the heat and humidity was unbearable. One morning, the troops were awoken by the sounds of cannon fire and were rained upon from Union cannonballs and modified shells, killing most of the regiment. With the majority of them dead, a small party of Union soldiers were dispatched to go ashore and either kill or capture the remaining survivors, but with damp powder due to either the humidity or from going ashore, those of the 3rd Lemoyne Regiment that survived were able to escape.
In Red Dead Online, if the player chooses Bayou Nwa as a region to set up a camp in, there is a possibility that their camp will be pitched at Copperhead Landing, despite it being in the neighbouring Bluewater Marsh region.