Look to your left. Now look to your right. There's a chance that only one of the three of you was in the county just a few decades ago.
In the last year the population in Loudoun has grown by more than 12,000 people, according to the Census' Population Estimates data.
That's almost 4 percent of the population, making it the 17th largest jump in population of any county in America.
The county grew from 337,248 people to 349,679 during the one-year period from July 1, 2012 to the same date in 2013.
Loudoun is also the second fastest-growing county in the country with a population of more than 250,000 people.