Like most cities, Hartford had its own dedicated quarantine zone after the outbreak of the cordyceps brain infection. However, the zone was known to have been falling apart at around the time of the game, and it is later confirmed that the military recently abandoned the zone and the people residing within. Some survivors, like Henry and Sam, chose to leave the zone in search of a safer place to live.
During the events of Left Behind, Winston mentions in a letter to his superior officer that refugees from the Hartford QZ were showing up at the mall where he was stationed, often infected; he was greatly angered by his superior's lack of response. Some of the Boston QZ residents discussed what was occurring in Hartford to each other, suspecting it was failing due to Firefly activity.
Ellie mentions that she heard that the situation in Hartford was bad from residents in Boston with Sam confirming that it was completely abandoned. Sam also speculated that the area was like Pittsburgh now; overrun with Infected and Hunters, due to there not being anyone left to maintain order.
- Hartford seems to have been the most recently-abandoned quarantine zone.