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.
The airport is located in Anne Arundel County, Maryland and is about 10 miles (16 km) south of Baltimore and 30 miles (48 km) northeast of Washington, D.C. Taxi â BWI. Taxi service is available from BMI to downtown DC.NTA events will be in the Walter E. Washington Convention Center (WCC) which is located between 7th and 9th Streets and N Street and Mt. Vernon Place in downtown DC, right across from the City Museum. Walter E. Washington Convention Center (WCC). 801 Mount Vernon Place, NW.