Given the number of federal agencies in the region, one would expect to easily find a Geographic Information System (GIS) conference pertinent to one's own specialty. It's not so easy with busy schedules and gridlock bearing down on us. Here is a quick overview of GIS Conferences in the area. Perhaps it will help you get to where you are needed most.
Maryland
Towson University GIS Conference
This conference usually sells out and is held in March.
Last one held March 19-20, 2007, Towson University, Towson, MD.
Virginia
Virginia Association for Mapping and Land Information Systems (VAMLIS) Conference
May 7-8, 2007
Richmond Convention Center, Richmond, VA
Washington, DC
- FOSE 2008
April 1-3, 2008
Washington, DC Convention Center - CDC/NCHS (National Center for Health Statistics)
Mostly exhibiting at other events. Here's a current 2007 list:
http://www.cdc.gov/nchs/events.htm - Conservation GIS — September 27-29, 2004
http://www.scgis.org/2004_Conference/conference_2004.html