The Pemaquid Point Light Station is a historic U.S. lighthouse located in Bristol, Maine, at the tip of the Pemaquid Peninsula.The lighthouse was commissioned in 1827 by John Quincy Adams and built that year. Due to poor workmanship (salt water was used in the mortar mix), the lighthouse began to crumble and was replaced in 1835. The second contract for the construction stipulated that only fresh water be used. Keeper Isaac Dunham oversaw the construction and wrote in a letter to the US Lighthouse Establishment that the agreement was upheld and the work went well.