The Sankaty Head Lighthouse is located on Nantucket Island. Built in 1850, it was automated in 1965 and remains operational. The 70-foot (approximately 21-meter) brick and granite structure sits atop a cliff at the end of what is now Baxter Road in Siasconset, flashing a white light every 7.5 seconds. It was one of the first lighthouses in the United States to be equipped with a Fresnel lens.