The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature in support of the U.S. Board on Geographic Names. The Historical Features layer (HISTORICAL_FEATURE) in the GNIS Web Map Service contains all features of all Feature Classes that have been designated historical. A historical feature is one that no longer exists on the landscape/seascape. The term makes no reference to the age, size, use, population or any other factor. See http://geonames.usgs.gov/domestic/feature_class.htm for feature class values and definitions. The HISTORICAL_FEATURE250 layer contains large features designated by the Geographic Names Office as ones that should be labeled on maps or displays with a scale of 1:250,000. See http://geonames.usgs.gov for additional information.