After the Great War, the Memorial was turned into something that resembles a water filtering facility with low-tech construction all around it and many pipes going in and out. It is not known if the original statue of Jefferson stands or not.
The game takes place in the year 2277 on the East Coast of what used to be the United States of America. The player character, known as the Lone Wanderer, is a young inhabitant of Vault 101, a fallout shelter in the Washington D.C. area. The vault has reportedly been sealed for 200 years, until the player's father, James, opens the only door to the outside world and disappears without any explanation.