pond island is located in penobscot bay, south of the western portion of brooksville and roughly west of little deer isle, one of the major islands of the town of deer isle. the island is geologically a combination of barrier sand dunes that were joined at a small knoll, with a small pond at its center that is connected to the bay via a tidal channel. the island is oriented roughly east–west, with slight tilt placing the western end further north than the eastern. off the western end is a smaller islet called john's head, which is joined to the island at low tide. the eastern end of the island is subject to erosion.