For details regarding school districts for each county, refer to the links below:
Arlington County: http://www.apsva.us/page/3001
City of Alexandria: http://www.acps.k12.va.us/enroll/zonelocator.php
Fairfax County: http://boundary.fcps.edu/boundary/
Loudoun County: https://webinter.lcps.org/Lcps_Locate/finder.aspx
Prince William County:
http://facilitiesservices.departments.pwcs.edu/modules/cms/pages.phtml?pageid=148645