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.
Explore some of the most famous landmark locations around Washington, DC on this guided, half-day sightseeing tour. Travel to Mount Vernon, George... from $44.00* George Washington's Mount Vernon by Water... Cruise on the Potomac River to Mount Vernon on this 7-hour boat trip from Alexandria. Listen to informative narration on board the boat, then take a...