On May 8, 1863, the Confederate army under the command of General Quincy Harris attacked the fort at night. Confederate soldiers climbed the trees near the fort and started shooting into the fort. Eventually, the Confederate Army broke through the north gate and US soldiers fought to protect the fort, but were outnumbered by large Confederate force. U.S. Army soldiers who surrendered or were captured were executed and burned.
In the New Hanover Gazette, U.S. Army veterans that survived the massacre remember the event. In addition, the newspaper states that details of massacre are still contested and that a memorial is planned for the site.
The fort is in a dilapidated state since it is no longer in use by the U.S. Army. The fort in 1899 is a hideout for the Lemoyne Raiders gang and it's leader Lindsey Wofford. Lindsey is wanted dead or alive by the Saint Denis Police Department. Players can earn $100 dollars for doing this bounty.
- In the basement of the building inside the fort, players can find a re-skin for Arthur's knife called "The Civil War Knife," a gold nugget, and a Civil War Hardee Hat.
- A Civil War Report document about the attack written by First Lieutenant Ronald Alger can be found here.
- Under the collapsed walkway is a chest that contains the Special Horse Medicine Pamphlet.
- Two cigarette cards can be found here.
- The massacre at Fort Brennand appears to be loosely based on the Battle of Fort Pillow (“Fort Pillow Massacre”) that took place on April 12, 1864 along the Mississippi River near the Arkansas-Tennessee border. Confederate soldiers massacred black Union troops and white officers who were attempting to surrender. Controversy continues today as to how many soldiers were killed, as well as to whether Confederate General Nathan Bedford Forrest ordered the massacre or the soldiers under his command acted spontaneously.