Home & Design Arlington’s 10 Most Expensive Neighborhoods Buyers pay top dollar for these upscale enclaves just outside the nation's capital. By: Arlington Magazine Staff April 19, 2019 #7Â Crystal Spring Knolls Quarter-acre lots are the norm in this established, tree-lined neighborhood, situated just north of Lorcom Lane and close to the Potomac River. Homes sold in 2018: 5- Advertisement - Average sale price: $1,376,300 Our Digital Partners Become a digital partner ...