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Minots Ledge Lighthouse (1860) under construction (National Archives photo)
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The United States has a diverse collection
of lighthouse construction types. The majority of today's surviving 595
lighthouses are land based; close to a fourth have foundations built in
the water. Lighthouses were built on land, in the water, on islands, on
top of ledges and cliffs, on breakwaters and piers, on caissons, and at
least five are on fort walls. The following list of lighthouse types is
organized by "onshore" or "offshore."
Politics, need, cost, location, and geography of the site, as well as
technology available at the time of construction influenced lighthouse
designs. Before the mid-19th century, lighthouse construction technology
required solid rock or other stable foundation soils; onshore towers sometimes
proved inadequate to warn ships off a shoal located offshore. In some
locations a lighted buoy or a lightship solved this problem. Riverine
and estuarine environments, however, often had unstable muddy and/or sandy
bottoms which could not support the heavy masonry towers then in vogue.
In areas such as the Chesapeake Bay, Delaware Bay, the Gulf of Mexico,
the Mississippi River delta, and the coral reefs of the Florida Keys,
the development of newer technology using screwpile, caisson, and skeletal
tower lighthouse construction was essential to adequately lighting the
marine hazards.
Onshore Lighthouse Types
Wood
Stone Masonry (Rubblestone
and Cut Stone)
Brick
Cast-Iron Plate
Skeletal (Iron and Steel)
Reinforced Concrete
Offshore Lighthouse Types
Straightpile and Screwpile
Caisson
Crib
Pier/Breakwater
Texas Towers
Sources: Ralph Eshelman, "Lighthouse Construction Types," CRM Bulletin, Volume 20, No. 8 (Published by the National
Park Service's Cultural Resources Program); Draft National Register of Historic Places Multiple Property Documentation form
for "Light Stations of the United States;" and the National Maritime Initiative's Inventory of Historic Light Stations
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