Jeff has correctly answered your question. But, as both a realtor and a parent of grown children, please bear in mind the following :
Fairfax County schools have an excellent reputation, and experience tells me , that virtually all of the elementary schools are quite good. While searching the Fairfax County Web site re schools, you might want to also check out those schools which offer special programs; i.e., language immersion.
But, you must also understand that there is no concept such as ABSOLUTELY FIXED SCHOOL BOUNDARIES. Depending upon population decline or increase, school boundaries will adjust. So, please never fall into the trap of buying into a specific neighborhood, because you are sure that your child will always be guaranteed a specific school.
If you would like to further discuss, I would be glad to do so.