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.
Mount Vernon is THE thing to do in DC! George Washingtonâs Estate, known as Mount Vernon, is located in Mount Vernon, Virginia, along the Potomac River and is probably the most scenic attraction in the Washington DC area. Mount Vernon, the home of George and Martha Washington, is the most popular historic estate in America.