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 located at 31Â°5â²35â³N 88Â°0â²40â³W / 31.09306Â°N 88.01111Â°W / 31.09306; -88.01111 (31.093170, -88.011209). According to the U.S. Census Bureau, the town has a total area of 1.9 square miles (4.9 km2), of which 1.9 square miles (4.9 km2) is land and 0.53% is water. As of the census of 2000, there were 844 people, 333 households, and 228 families residing in the town.