Van Buren was the codename of a canceled role-playing video game developed by Black Isle Studios. It was intended to be the third game in the mainline Fallout series. Set in the year 2253, the plot of Van Buren revolved around an escaped prisoner who would explore the American Southwest while being pursued by robotic prison guards. The main antagonist was a mad scientist named Victor Presper, who planned on using the prisoner as an inadvertent vector to spread a deadly virus. Gameplay would have included a mixture of real-time and turn-based combat. The player would explore the map with a team of non-playable character (NPC) companions. Each NPC would make their own independent decisions which would affect the story.
Van Buren was Black Isle's second attempt at making a third mainline Fallout game. After the initial project was canceled, designer Chris Avellone worked on a Fallout themed tabletop role-playing game in his spare time. He ran two separate games with Black Isle members, and the actions of the players inspired nearly all of the content in Van Buren. The development of Van Buren was hampered by the financial struggles of publisher Interplay Entertainment. When the Black Isle game Baldur's Gate III: The Black Hound was canceled, Avellone resigned. Josh Sawyer replaced Avellone as the lead designer, but he too resigned due to mismanagement from Interplay. In December 2003, Van Buren was canceled in favor of Fallout: Brotherhood of Steel. Some of the story elements from Van Buren were later used in the 2010 game Fallout: New Vegas. Fans have attempted to recreate and finish Van Buren using a leaked playable demo and 700-page design document as reference.