Generally, for the conterminous United States, the North American Datum (NAD) shift amounts to about 210 meters. This shift occurs because of the change in shape of the spheroid used to define the datum.
A feature is something shown on a map, and it has characteristics or properties, which can be represented in feature-based Digital Line Graph (DLG) data using attributes and values.
The USGS Geographic Names Project maintains an active and extensive program to add features not in the database, primarily through partnerships with Federal, State, and local agencies, and with other organizations having relevant data.
Often, users of the data can misinterpret the content of certain fields. The field entitled "USGS 7.5' map" may be one of these fields.