Until 1863 the design and construction of lighthouses was the responsibility of the
Corps of Topographical Engineers; this resulted in a rivalry with the longer-established
Army Corps of Engineers, which built fortifications and had responsibility, as it does today, for waterway improvements. The
Chief Engineer of the Army Corps of Engineers,
Joseph G. Totten, personally took charge of the project to design and construct a permanent lighthouse on Minot's Ledge. Totten's design was as simple as it was effective. With extensive experience building fortifications, Totten fully appreciated the permanency and strength of granite constructions. He designed the lighthouse so the first 40 feet of lighthouse would be a solid granite base weighing thousands of tons. To secure the lighthouse to the ledge, he had several massive iron pins emplaced so that the lighthouse would be literally pinned to the ledge by its own weight. Working on the ledge could take place only in conditions when it was exposed at low tide and the sea was calm, so construction took years. Work started on the current lighthouse in 1855, and it was completed and first lit on November 15, 1860. With a final cost of $300,000, it was the most expensive light house that was ever constructed in the United States to that date. The lighthouse is built of large and heavy dovetailed
granite blocks, which were cut and dressed ashore in Quincy and taken to the ledge by ship. The lighthouse was equipped with a third-order
Fresnel lens. The
light signal, a 1-4-3 flashing cycle adopted in 1894, is locally referred to as "I LOVE YOU" (1-4-3 being the
number of letters in that phrase), and it is often cited as such by romantic couples within its range. Minots Ledge Light was automated in 1947. ==Historical information==