“Northern Virginia” is a local colloquialism for the counties closest to DC. It does not mean the top half of the state.
Over the years, I sporadically have received appointment requests for locations that are no where close to Northern Virginia but are technically in the top half of Virginia. This post was prompted though by someone booking from a location adjacent to, but not even in the top half of Virginia. They knew I only went to Northern Virginia, but was their location close enough? (I don’t want to put them on further blast so feel free to ask me at your next appointment.)
The precise definition of Northern Virginia is always a good debate. People have been trying to expand it for ever. I grew up in Vienna, clear NoVA territory, so my definition was decided long ago. It is indeed heavily prejudiced by how distance was measured when I was a kid but also by how much worse traffic has gotten over the years.
My Northern Virginia definition is Arlington, Fairfax, and Prince William counties (all cities and towns contained therein), plus the border towns of Ashburn, South Riding, and Sterling. It is not up for debate unless you have managed to get from Haymarket to Triangle during rush hour in less than an hour. And it’s not going to be a debate, it’s just me asking for your secrets.