Percy's copy of the Map of the most Inhabited Part of New England is notable for the annotation in pencil and ink of several roads across New England. The original, printed map included a few roads, marked as double lines, but these were by no means all the roads that crossed the region. The inked lines on the face of the map all link towns and printed roads. Without further clues, such as lettered annotations, it is impossible to say with certainty who made these annotations on the map's surface. It might indeed have been Percy himself; or it was a fellow officer. Either way, this map clearly served as a strategic planning document.