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.
SEPTEMBER 24 â 27, 2015 â¦ The City of Mount Vernon, New York is 4.4 square miles and home to approximately 67,292 residents, making it the 8th largest city in New York State.