I have 2 cousins who live in Falls Church City and know that that isn't a county.
According to the United States Census Bureau, the city has a total area of 2.0 square miles (5.2 km2), all land, no water.[20] Falls Church is the smallest independent city by area in Virginia. Since independent cities in Virginia are considered county-equivalents, it is also the smallest county-equivalent in the United States by area.