New York City
New York City was a pre-War city in the United States.
In 2065, a nuclear reactor, struggling to power the population of 17 million people, went supercritical for a period of about 5 minutes. While there was no explosion, the NYC incident coined the term "hot summer" for a heat-related electrical overload on nuclear systems.
New York City is mentioned in the Fallout Bible 0 and also in a Capitol Post article about the disbanding of the United Nations in Fallout 3. It is also mentioned in the Fallout: New Vegas add-on, Dead Money.