In 2007, when cartographer John Cloud was cataloging more than 7,000 maps at the National Archives in Washington D.C., he came across two that immediately chilled him.

“In fifteen minutes, I found two different maps done by Alaska Natives working cooperatively with the Coast Survey (present day NOAA) in the nineteenth century, and nobody knew about this. There was no memory of this,” said Cloud, who at the time was a historian for the National…