I had discovered this shortly after moving here, but would like now use it to reiterate how strange and convoluted Virginia can be. And let's not get me started on the road signs:

All cities within the state are independent of counties, though towns may be incorporated within counties. However, Arlington has no existing incorporated towns because Virginia law prevents the creation of any new municipality within a county that has a population density greater than 1,000 persons per square mile. Its county seat is the census-designated place of Arlington, which is co-extensive with Arlington County; however, the neighborhood of Courthouse is often thought of as seat by residents.