What properties contribute to a district eligible for listing in the National Register?
Buildings, structures, sites, objects, and districts can be listed in the Register. A National Register historic district may be as small as a few buildings, or as large as an entire downtown business district, neighborhood, or community in which historic properties that are associated with a particular time or theme in history predominate. Often their collective significance may be greater than that of any one building or site. Generally a district must be at least fifty years old, but not all places that are fifty years old are eligible for listing. The district must possess significance in American history, architecture, archeology, engineering, or culture and retain its historic integrity. This means that the district must not have lost the physical qualities that convey its significance. Within a district, most individual properties that are at least 50 years old contribute to its significance. Most properties that are less than 50 years old are not considered to contribute. The N
