The FDNY mapping project was started after the tragic events of 9/11.
A comprehensive mapping of FDNY firehouses did not exist, certainly not on the web. As out-of-town firefighters attended funerals throughout the city, we helped produced these very basic locator maps showing firehouse locations, companies assigned as well as the Divisional organization at the time.
Time has not allowed us to update the maps, so these continue to serve as a snapshot of firehouse locations and resources immediately following September 11, 2001.
These maps have proven to be very popular. In fact even today, typing “FDNY maps” into Google will rank these pages very high.
Here is a newer, on-line source that you may also find useful.