[coordinate systems, geodesy]
Abbreviated as NAD 1927. This was the primary local horizontal geodetic datum and geographic coordinate system that was used to map the United States during the middle part of the twentieth century. NAD 1927 is referenced to the Clarke spheroid of 1866 and an origin point at Meades Ranch, Kansas. Features on USGS topographic maps, including the corners of 7.5-minute quadrangle maps, are referenced to NAD 1927. It has gradually been replaced by the North American Datum of 1983.