Like many areas within Boston, the Financial District has no official definition. It is roughly bounded by Atlantic Avenue, State Street, and Devonshire Street. Parts of the Financial District are in various USPS postal ZIP Codes including 02108, 02109, 02110, and 02111. The T subway station at Atlantic Avenue and State Street is officially designated “Aquarium/Financial District”.

The area includes Post Office Square, the Exchange Place and International Place complexes, and the landmark Custom House Tower(now a private condominium).