District of Columbia Economic Impact Notification Act

District of Columbia Economic Impact Notification Act - Requires a Federal agency that proposes to carry out any program or activity that would result in the transfer of 50 or more employees whose official station or agency is located in the District of Columbia to another station or agency outside of the District for permanent duty to: (1) prepare a District of Columbia economic impact statement; (2) submit the statement to specified congressional committees within 12 months before such program or activity is scheduled to begin; (3) submit the statement to the National Capital Planning Commission, the Congress, the Administrator of General Services, the Mayor of the District, and the District of Columbia Council; and (4) publish the statement in the Federal Register. Provides that the entering into of a contract to construct a new facility or to lease an existing one as the official station or agency of employees of a Federal agency shall be considered a program or activity carried out by the agency. Requires congressional approval before such program or activity can be carried out unless an emergency exists and the program or activity would be in the national security interest of the United States. Sets forth provisions relating to the preparation of a District of Columbia impact statement. Requires the headquarters functions of each executive department to be carried out in the District. Defines "Federal agency" as an executive department and "headquarters functions" as a Federal function or activity relating to the administration of national laws, the formulation of policy directives and regulations, the needs of the President for consultation with executive department officers, or any other necessary activities for the efficient functioning of the Government, including related administrative and support services.