The locations of National Register properties and districts (at least for all showing latitude and longitude coordinates below), may be seen in an online map by clicking on "Map of all coordinates".[a]
The following are approximate tallies of current listings by county. These counts are based on entries in the National Register Information Database as of April 24, 2008[2] and new weekly listings posted since then on the National Register of Historic Places web site.[3] 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.[4] 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 latitude and longitude information provided in this table was derived originally from the National Register Information System, which has been found to be fairly accurate for about 99% of listings. Some locations in this table may have been corrected to current GPS standards.