Googled: location of fallout shelters/blast shelters U.S., community shelters, nuclear winter, surviving nuclear winter.
Scenario: Nuclear winter, basically. Some people survived the initial war, several decades ago, but the long-term climate effects are such that everyone is ultimately doomed. There are only a handful of survivors left, living in Cold War-era underground fallout shelters.
My question: Where in the U.S. would it be most likely for the last survivors to be? I understand that there are still shelters all over the place, and that there were a few attempts at making community shelters in the 1960s. Are there any that would be more likely to hold out the longest?