Jake Green narrates at the beginning of each episode saying that "nuclear attacks destroyed 23 American cities". However, throughout the series, a total of 24 cities are cited as destroyed by the bombs.
Twenty two cities are marked on the map in the Black Jack episode: Seattle, San Diego, San Francisco, Los Angeles, Cedar City (Utah), Phoenix, Denver, Lawrence (Kansas), Dallas, Houston, Minneapolis, Chicago, Detroit, Philadelphia, Pittsburgh, Hartford, Boston, Washington DC, Baltimore, Charlotte, Atlanta, and Miami.
Two additional cities are mentioned in various other episodes: Indianapolis and Norfolk.