National Register Information System

The National Register Information System (NRIS) is a database of properties that have been listed on the United States National Register of Historic Places. The database includes more than 84,000 entries of historic sites that are currently listed on the National Register, that were previously listed and later removed, or that are pending listing. The database includes approximately 45 pieces of data for each listed property. Accuracy of the NRIS database may be imperfect. For example, a 2004 paper addressed accuracy of spatial location data for part of the NRIS content.