The locations of National Register properties and districts (at least for all showing latitude and longitude coordinates below), may be seen in a Google map by clicking on "Map of all coordinates".
The list is generally grouped by quadrant. The Northwest Quadrant has almost 400 listings, so it is further divided into three parts. The part of the NW Quadrant nearest the National Mall (east of Rock Creek and south of M Street) is grouped with the Southwest quadrant and called "central Washington" for the purposes of this list. The remaining sections are of the NW Quadrant are divided between areas east of Rock Creek and areas to its west. The following are approximate tallies of current listings by area.
Note that the White House, the Capitol, and the United States Supreme Court Building are recorded in the National Register's NRIS database as National Historic Landmarks, but by the provisions of the Historic Preservation Act of 1966, Section 107 (16 U.S.C. 470g), these three buildings and associated buildings and grounds are legally exempted from listing in the National Register.
^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. For about 1% of NRIS original coordinates, experience has shown that one or both coordinates are typos or otherwise extremely far off; some corrections may have been made. A more subtle problem causes many locations to be off by up to 150 yards, depending on location in the country: most NRIS coordinates were derived from tracing out latitude and longitudes off of USGS topographical quadrant maps created under the North American Datum of 1927, which differs from the current, highly accurate WGS84 GPS system used by most on-line maps. Chicago is about right, but NRIS longitudes in Washington are higher by about 4.5 seconds, and are lower by about 2.0 seconds in Maine. Latitudes differ by about 1.0 second in Florida. Some locations in this table may have been corrected to current GPS standards.
^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 only modify the area covered by an existing property or district, although carrying a separate National Register reference number.