The list of America''s nationally registered historic places extends special legal and protective recognition to districts, sites, buildings, structures, and objects considered to be worthy of long-term preservation. The geographical implications of listing and valuing particular kinds of historic sites reveals an American preservation ethic, and a metamorphosing set of values. This study identifies three unique preservation ethical eras, and it maps the sites which were selected during those eras. Varying emphases on European settlement, village archeology, commercial architecture, and planning factors define era categories. With an added emphasis on the treatment of Native American Indians, the study serves decision-makers in discerning historical significance and cultural value.