United States National Register of Historic Places listings
The National Register of Historic Places in the United States is a register including buildings, sites, structures, districts, and objects. The Register automatically includes all National Historic Landmarks as well as all historic areas administered by the U.S. National Park Service. Since its introduction in 1966, more than 90,000 separate listings have been added to the register. Current listings by state and territory. The following are approximate tallies of current listings by state and territory on the National Register of Historic Places. These counts are based on entries in the National Register  Information Database as of April 24, 2008, and new weekly listings posted since then on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings and the counts here are approximate and not official. New entries are added to the official Register on a weekly basis. Also, the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number. The numbers of NRHP listings in each state are documented by tables in each  of the individual state list-articles. A map index to the state lists of NRHPs. "Additional U.S. NRHPs that are not on the map: American Samoa, Guam, Northern Mariana Islands, Puerto Rico, U.S. Minor Outlying Islands, U.S. Virgin Islands"