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Bathymetry for Albemarle Sound was derived from twenty-five surveyscontaining 187,065 soundings. Two older, less accurate, overlapping surveyswere omitted before tinning. The average separation between soundings was 115meters. There was one survey in the west that dated from 1874. Theremaining twenty-four surveys used dated from 1917 to 1942. The total rangeof sounding data was 0.7 meters to - 14.3 meters at mean low water. A meanhigh water value of 0.2 meters was assigned to the shoreline. Eight pointswere found that were not consistent with the surrounding data. These wereremoved prior to tinning. DEM grid values outside the shoreline (onland) were assigned null values (-32676).Albemarle Sound has forty-nine 7.5 minute DEMs and four one degreeDEMs. The 1 degree DEMs were generated from the higher resolution 7.5minute DEMs which covered the estuary. A Digital Elevation Model(DEM) contains a series of elevations ordered from south to northwith the order of the columns from west to east. The DEM isformatted as one ASCII header record (A- record), followed by aseries of profile records (B- records) each of which include a shortB-record header followed by a series of ASCII integer elevations(typically in units of 1 centimeter) per each profile. The lastphysical record of the DEM is an accuracy record (C-record).The 7.5-minute DEM (30- by 30-m data spacing) is cast on theUniversal Transverse Mercator (UTM) projection. It provides coveragein 7.5- by 7.5-minute blocks. Each product provides the samecoverage as a standard USGS 7.5-minute quadrangle but the DEMcontains over edge data. Coverage is available for many estuaries ofthe contiguous United States but is not complete.