In or Somewhere Around Pittsburgh, PA in 1991
Although Charlie never outright states where he lives, in order to try and conceal his identity, he dates each letter that he writes in the novel. The first letter he write is on August 25, 1991, and the last on June 22, 1992. Readers can figure out that he lives in or around Pittsburgh, Pennsylvania, because of many clues that are given for the duration of the reading. One reason we know this to be true is because Charlie's brother goes to Penn State, which is about 140 miles from Pittsburgh. Later in the book, Sam also decides to go to school there. Using this information, we could assume that they chose to go to a nearby college. In addition, Charlie's dad's relatives supposedly live a "two-hour drive" away. One can safely assume that his family lives in a surrounding state, such as Pennsylvania. For a final piece of evidence, Charlie says that they drive through a tunnel called, "the Fort Pitt Tunnel." Indeed, there is a tunnel in Pittsburgh named the Fort Pitt Tunnel.