The following is a timeline of known, scheduled, or planned dates for various events within Fallout: Dallas.
- October 23 - The Great War occurs over a two-hour period, leaving the United States in an atomic wasteland.
- The East Coast receives several bomb hits around 9:45 AM EST.
- As news of bombings comes in, citizens in Dallas who live around Vault 45 and have been registered to enter begin fleeing to the Vault. The doors close safely before the bombs land on Dallas at 9:58 EST (8:58 AM in Dallas), and the new Dwellers of the 1,000-capacity vault begin accomodating to their new home.
- October 23 - The Great Uprising occurs.
- By the ten-year mark of Vault 45's run, Vault technicians using data from Vault 111 have finished their design, construction, and enhancement of the Vault 45 cryosleep system. The system is designed to allow the 250 followers of the Overseer to hibernate until the world has become habitable enough to be ready for their arrival to take over the United States by way of the Enclave project - that is, 200 years later. 750 pods exist in total - three batches of 250 pods each available in case anything happened to any of the other pods, thus forming a full doubled-up backup system; the pods went through three different primary development versions, and the older ones were left as backups.
- At some point, one of the Overseer's 250 followers - a former oil tycoon named Earl Ruby - leaks information about the Overseer's plot to the dwellers, realizing that he could incite an uprising and join the side with more people.
- The Vault 45 dwellers, having learned of the plot to let the Vault die while the Overseer's army hibernates, overtake the Overseer's followers by virtue of the dwellers having an enourmous number of people to fight. About 300 of the approximately 1,000 Vault dwellers die during the ensuing fight, leaving only 712 dwellers. 24 of the Enclave remain alive, having surrendered after the dwellers killed 90% of their comrades, including the Overseer himself.
- Once the dwellers have verified the working condition of the cryosleep pods, with three located in each of the 250 Overseer's followers' living-quarters rooms, the dwellers enter the pods. They graciously allow the surrendered 24 personnel to enter cryosleep as well, as the defeated Enclave members agreed to provide the dwellers with full access to all of the armory items and agreed to teach the dwellers how to use items such as the Vertibirds.
- The first of the Vault 45 dwellers begin to emerge from cryosleep, 200 years after entering. From this point on, dwellers begin the process of setting up facilities for caring for other dwellers emerging sleep.
- October 21
- With access to the Overseer's panel, granted by the surrendered followers of the Overseer, the dwellers open the blast doors of Vault 45 and begin to set up shacks around the Vault. The dwellers also make contact with the residents of nearby Marsalis on the first day.
- October 23
- Fallout 4 begins.
- All Vault 45 dwellers who had entered Generation C cryopods (which had the most accurate cooldown-timers) emerge on this day.
- A Brotherhood of Steel patrol makes contact with the newly-emerged Dwellers. Warning the dwellers that many Raiders exist in the area, and having learned of the Vault's immense armory, the Brotherhood offers to defend the Vault, if the dwellers agree to let the Brotherhood use the site as a secondary headquarters and have shared control over the armory and the Vault's massive power generators. The dwellers agree, and the Brotherhood of Steel thus gains control of the Vault and begins setting up fortifications around the perimeter. An air duct system is also installed, due to the fact that two hundred years has made the air hospitable enough to spread freely in and out of the Vault.
- Fallout: Dallas begins (exact date in January determined by the real-world day of the month in which the player joins). Having been told by Dr. Jackson what has happened since you entered cryosleep, you are given a memory check as to what role you played in the Great Uprising (determining your SPECIAL traits and Tag skills, unless you opt to select different results from his suggestions). You then leave the Vault to explore.