An 1883 article from the Weekly Citizen (Tuscon) mentions the naming of Battle Flat. In 1864 Arizona was home to Indian tribes and settlers and it was not uncommon for fights between the two sides to ensue. About 100 miles east of Prescott one of these fights took place in May of 1864 and this location became known as Battle Flat. Several men were camped in the small open area where they were attacked by Apache Indians.
Article: "Battle Flat Fight," Weekly Citizen (Tucson), October 1, 1883.