Portsmouth Harbor Light, off Portsmouth, New Hampshire, in the entrance to the Piscataqua River near the little town of New Castle. The historic, cast-iron, brick-lined lighthouse, located within Fort Constitution was erected in 1878 on the foundation of an earlier tower. The current light is a fixed green signal visible for 12 nautical miles. Other structures at the light station still standing include the 1903 oil house (restored in 2004) and the 1872 keeper's house -- currently United States Coast Guard offices. Photo by Carol Highsmith, 2017.