Great Lighthouses
The coastlines of the United States are long and rugged. Consequently they are peppered with great American lighthouses all along the east and west coast as well as the shores of the Great Lakes. 
Placed in strategic spots to provide a guide or a warning to the ships at sea, these lighthouses would mark a safe harbor or warn against dangerous shoals that would rip the bottom of their ship if they ventured too close.
Today, lighthouses are part of our history and seafaring lore. Each one is an adventure as well as an education to any tourist or sightseer. They are great places to visit if there is one near or if you are planning a vacation near the ocean or the Great Lakes region.
This is a series on lighthouses in America. It is meant to provide a very brief description of many of them and help point you in the proper direction to find them.
We will be splitting up our series into the following geographical sections: Northeast, Mid Atlantic, Southeast, Gulf Coast and West Coast, and the Great Lakes.
History
Lighthouses have been providing navigational help since men have been traveling the sea. They were used to denote shorelines, warn of hazardous shoals and mark the entrance to safe harbors for ships during bad weather and at night. At the beginning of the era of flight, they also helped provide for aerial navigation.
The original method was a "keeper" would simply light a fire on the shoreline, or on a bluff.
Eventually the towers were built to extend the range of vision for the ships farther out to sea.
(Even though this is not in the U.S.A.) The most famous of the ancient lighthouses was the one at Alexandria on the island of Pharos in Greece. It was built in the third century BC and stated to be over 400 feet high in its day. Today it is only ruins. However, It is considered one of the seven wonders of the ancient world.
How They Work
For centuries the operational methods for lighthouses did not change. In ancient times a tower with a small living space (in many cases) in some key location would provide its light from a fire.
Most had some sort of reflective surface behind the fire, simple mirrors served to reflect the light out to sea to improve its visibility. The keeper's job was to stoke the fire at night and during times of low visibility like foggy days.
As mans understanding of technology changed so did the light methods for the keeper. After the simple fire, modern lighthouses made use of lamps that used either whale or colza oil to power these lamps.
Later lighthouses used kerosene and some Carbide (Acetylene gas) This source of light was shaped, or concentrated, into a beam by an optical lens to increase the distance that the light could be seen from.
Parabolic mirrors shaped the lamplight and allowed for rotation of the beam so ships at sea could see the side of the beam as well as the point of light from great distances. However, only about 20% of the available light could be focused limiting the distance and effectiveness of lighthouses.
Fresnel Lens
In 1822, the invention of the Fresnel lens allowed for 85% of the light to be focused and beamed out. A Fresnel lens is simply a piece of glass that is flat on one side (the side toward the light source) and with concentric rings of ridges on the other. Each ridge is thinner which focuses light toward the center.
These lenses are used today in many different applications from traffic lights to magnifying tools.
Eventually lighthouses were converted to electricity and use rotating beacons for greater power and remote control eliminating the need for a keeper. These require very little maintenance and use high intensity lights.
Very few lighthouses are now in service throughout the United States. This is due to the development of modern electronic navigational aids like GPS that can provide instant location information within a few feet anywhere on the planet.
Preservation
As lighthouses have become less essential to navigation, many through neglect have been lost to us. However, many still exist and can and should be visited throughout the United States.
No matter if a lighthouse is in service or not, they make a great addition to either a day trip or a much longer tour of our coastlines.
Today, many people make a point to visit and photograph them. Some have actually become destination points for people who have come to love them, their history and lore. Most all have some sort of museum attached that will provide the history and story of their existence.
Where To Find Them
Many States preserve and provide access to lighthouses. There are far too many of them to list here. Refer to your local state web pages for additional information and exact locations. The following are just a few of the more popular destinations and a little about them to assist you in deciding where to visit first.