The Horn Papers were a genealogical hoax consisting of forged historical records pertaining to the northeastern United States from 1765 to 1795.
The Horn Papers first appeared publicly in 1932 in letters sent from Topeka to the editors of the Washington, Pennsylvania, Observer and the Waynesburg, Pennsylvania, Democrat-Messenger in which their author claimed to possess important historical documents relating to the area.
Although a minority opposed Horn, on August 11, 1936, his claims appeared to have been corroborated when he announced that he had dug up two lead plates dated 1795 in a location predicted by the papers.
The apparent find increased the confidence of members of the Greene County, Pennsylvania, Historical Society, who sponsored the reissuing of the papers in book form.
A year later, a report by a committee of representatives of historical societies from the region concluded in The William and Mary Quarterly that the first two volumes were substantially hoaxes.