The datum is defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all bench marks resulting from the adjustment. A total of 106,724 kilometers of leveling was involved, constituting 246 closed circuits and 25 circuits at sea level.
George Washingtonâs Mount Vernon is located roughly 15 miles south of Washington, D.C. and 8 miles south of Alexandria, Virginia on the banks of the Potomac River, at the southern end of the George Washington Memorial Parkway.
There are 15.10 miles from Fairfax to Washington in northeast direction and 9.01 miles (14.50 kilometers) by car, following the US-50 route. Fairfax and Washington are 24 minutes far apart, if you drive non-stop. This is the fastest route from Fairfax, VA to Washington, DC. The halfway point is Falls Church, VA. Fairfax, VA and Washington, DC are in the same time zone (EDT). Current time in both locations is 1:38 am.