Department of the Interior

The Department of Interior (DOI) is located between 18th and 19th Streets and between “C” and “E” Streets in Northwest, Washington, DC.  The structure, which occupies two square blocks, was built between 1935 and 1936 and has housed the Department of Interior since it completion.  The building, designed in a Neo-classical style, consists of a central spine main corridor running north-south with 12 opposing wings aligned east and west.  The building’s seven floor levels, basement and central penthouse contain approximately 1.3 million gross square feet of which 750,845 is classified as able to be occupied.

The Main Interior Building modernization construction plan is based on the building being 80% occupied during construction at any one phase.  The 6-phase construction plan requires that 1 of 6 wings of the building be vacant at any one time during each construction phase. DOI has relocated agency personnel, occupying the entire Wing 6 (250,000 square feet), to an external leased swing space during construction Phase I of the project. Upon completion of the modernization project, displaced DOI personnel will move back to the Main Interior Building as well as other personnel from external expiring leased spaces.  Total project total cost is $219 million.

Last Reviewed 2015-08-10