A map of the battlefield of Antietam held by the New York Public Library that shows the location of graves of soldiers killed in the 1862 U.S. Civil War battle is the subject of a piece in today’s Washington Post.

Civil War historians are hailing it as an important new way to visualize the toll of the huge battle outside Sharpsburg, Md., in 1862.

“Every one of us who’s looked at this absolutely flips out,” said Garry Adelman, chief historian for the Washington-based American Battlefield Trust, which works to preserve historic battlefields. “This will reverberate for decades.”

The map is the only one of its kind known to exist. It was digitized by the New York Public Library, which owns it, and was spotted online by local historians a few weeks ago.

The map doesn’t just mark graveyards, it notes the burial locations of specific regiments and brigades—and in 45 cases, individual soldiers.

The Unwritten Record, a blog by staff at the U.S. National Archives’s Special Media Archives Services Division, announced last month: “Civil War maps are always popular at the National Archives, and the Cartographic Branch is pleased to announce the digitization of over 100 Confederate maps from Record Group (RG) 109.  All are now available to view or download through our online catalog.” [Texas Map Society]

Politico maps the locations of Confederate monuments in the United States, and correlates their locations with where African-American populations are concentrated.

The majority of these symbols were dedicated between 1900 and 1920, when the South enacted Jim Crow laws aimed at resegregating society or discriminating against blacks. There was also a notable spike in new symbols during the height of the civil rights movement.

Among states with the highest proportion of African-Americans, Mississippi, whose population is 37 percent black, has more than 130 commemorations, while Louisiana, which is 32 percent black, is home to 91 symbols. Georgia, whose population is 30.5 percent black, has 175 monuments.

There’s an unstated implication there.

Previously: Gettysburg Electric Map to Reopen in June; The Return of the Electric Map.

Previously: The Return of the Electric Map.