Vault 49 was a Vault-Tec Vault in which the farm house was designed to fail after 120 years. This Vault was located on the outskirts of Jacksonville, Florida and eventually fell into chaos.
On the inside, two teams arose when the farm house shut down, Civilians and the Vault Security. The Vault Security occupied the Atruim and upper levels, which included the exit to the vault, while the residents occupied the rest which included the vault's nuclear reactors. Eventually after a year of fighting (none violently, almost becoming violent a few times), the citizens broke into the armory and took as many weapons as possible, as the armory was under stocked. This resulted in a three way war underneath the ground. Time grew short, and the overseer was killed by an un-named man with assistance of the overseer's Security Chief and son; Lucas Wilkinson. The two were sent outside to scout the surrounding area when the un-named man heard his sister die. Enraged, he went back into the vault to destroy the vault door control pod on the inside and locked the remaining people inside while also destroying the outside pod as well. The two left, only for several years later the un-named man's son and daughter were searching for their parents made their second stop at this very vault, the vault were their father was born, and the son was able to repair the outside control pod and opened the vault once more only to find one cannibalistic man on the other side. That man was the leader of the group that killed Vault 49's overseer. He had survived by eating his fellow teammates, but he was quickly shot to death by the children of the un-named man who was probably dead by then. After those major points in history, it was all disappointed raiders. Tl:dr The vault was abandoned after 122 years.
Construction of Vault 49 in Jacksonville started in 2061 and ended in 2075. People began signing up for spaces in 2074. The only reason Vault 49 took long to build was complications with landscape, considering Florida is very close to sea level. So due to complications with flooding construction dates were postponed.