Fort Mercer

Fort Mercer is a location featured in Red Dead Redemption in the Río Bravo region of the New Austin territory. Fort Mercer is associated with an outlaw hideout, and the location of Bill Williamson. Fort Mercer also might have been a fort used during the Mexican-American war as it is near the border with Mexico.

Fort Mercer is an important storyline location, as it is here that Williamson remains protected in the fortifications alongside his outlaw companions. It the main location for the mission The Assault on Fort Mercer.

Storyline
Marston seeks out Williamson to appease the demands of Agent Edgar Ross, and during a verbal confrontation where Marston appeals to Williamson to surrender, Marston is severely wounded. After rescue and recovery, thanks to Bonnie MacFarlane, Marston starts to organize a raid on the fort. Marston's plan requires the assistance of various characters: Marshall Leigh Johnson, Nigel West Dickens, Irish and Seth Briars. Each character offers different resources and abilities for Marston to complete his mission:
 * Marshall Johnson provides his skills as a veteran gunfighter, as well as the services of his deputies Jonah and Eli.
 * Nigel West Dickens arranges an armoured stagecoach to assault the fort.
 * Seth Briars provides a unique distraction for outlaws guarding Williamson.
 * Irish supplies Marston with a mounted machine gun.

Singleplayer
After Williamson has been cleared from the fort, it is available as a standard gang hideout later on(after you are able to return to the U.S. from Mexico). The Banditos have now taken over.

Leon Galindo will be outside the walls, at which point he will vault over the wall. Climb up, kill several banditos, drop down and open the front gates for him. After this, simply kill all remaining banditos in Fort Mercer, resulting in the 3 bandito Leaders (enemies with slightly more health than regular ones) will burst out of the treasure room. The hideout is complete once the Gunslinger enters the treasure room too. Also, a Semi Auto Pistol is located on the boxes in the treasure room and take all the treasure. There is also a safe on the upper level of the fort that can be cracked, however, doing so without wearing the bandana will result in a loss of 100 honor (as with any other safe).

Occasionally, the Gunslinger will get stuck behind a wooden rack-like object leaning against a wall. Simply run into this object to make it fall over and he will continue on.

There is a bug in which after introduces himself he will stand motionless making you unable to proceed.

Multiplayer

 * In multiplayer free roam, the LeMat revolver is located here. Also a Mounted Machine Gun is located up top on a roof, You can use it for when you're in a "Bad" spot.

Achievements
Fort Mercer is associated with several hideout achievements:

Trivia

 * Fort Merceris a real fort that was made during the American Revolution. It sits on the banks of the Delaware River and was headed by George Washington.
 * Fort Mercer is very similar to that of Fort Diego's layout.
 * It is possible to duel the gunslinger, Leon in single player.
 * Mercer comes from the Old English Merc or Myrce meaning "Borderland". This is plausible as Fort Mercer is on the US-Mexico border.
 * During the Exodus in America mission, Jake will tell the player that, although Fort Mercer has been abandoned for years, it was originally occupied by American soldiers during the Mexican War. He says that even though he heard they left to fight Indians in the North, it's possible they "got tired of being soldiers and went looking for gold, you know how things is." It's possible that this is a reference to the group of soldiers who hid the gold found during the Treasure Hunter Challenges, considering that Fort Mercer has a treasure room located within its walls.

Gallery
Fort Mercer