"As a result of the planned 2009 Presidential Inauguration in Washington, DC on January 20, 2009, the FAA at the request of the Department of Homeland Security and Department of Defense as part of the airspace security measures will be modifying the Washington Air Defense Identification Zone (ADIZ) and Washington Metropolitan Flight Restriction Zone (FRZ) with additional flight restrictions between the hours of 1000-1800 local."
The impacted zone is as follows:

For complete details and additional information on the advisory, please visit:
www.faa.gov/news/media/public_advisory_inauguration_2009.pdf
For additional advisories and Notice to Airmen (NOTAMs), please visit: