Literary Treasure Hunt: Clue #6

To find this sixth copy of Thrones, solve the clue and be the first to visit the site and claim your prize.  Good luck!

Once the home of Joseph Nourse, first Register of the Treasury, this Federal period structure was described as "...one of the very finest and most beautiful houses in the United States," by architectural historian Fiske Kimball. Today, this beautiful property is a museum dedicated to educating the public about life in Washington, DC during the early years of the Republic. It is also the home of The National Society of The Colonial Dames of America. (Hours of operation are Tuesday through Saturday 10 to 1.)