Why Did They Called It the Manhattan Project?The New York Times has a wonderful article on that question. In The Manhattan Project (Black Dog & Leventhal), published last month, Dr. Norris writes about the Manhattan Project's Manhattan locations. He says the borough had at least 10 sites, all but one still standing. They include warehouses that held uranium, laboratories that split the atom, and the project's first headquarters - a skyscraper hidden in plain sight right across from City Hall.
The article has a video interview with Stan, who I had a chance to meet a few years back. In addition, they also have nice interactive map of the various sites in NYC.