According to OPM, "Federal agencies in the Washington, DC, area are CLOSED" on Monday.
According to WJLA TV-7, Northern Virginia school systems that are closed tomorrow include:
Alexandria City
Arlington County
Clarke County -- through Tuesday
Fairfax County -- through Wednesday
Falls Church City
Fauquier County
Frederick County
Loudoun County -- through Tuesday
Manassas City
Manassas Park
Page County -- through Tuesday
Prince William County
Shenandoah County -- through Wednesday
Stafford County
If you know of any other closings, please mention them in the comments section. Thanks!