A lighthouse is a structure, usually a tower, that is designed to emit light from a system of lamps and lenses, and used to serve as a navigational aid for maritime pilots at sea or on inland waterways.

Normally, lighthouses mark dangerous coastlines, hazardous shoals, reefs, and safe entries to harbors, and can assist in aerial navigation. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and the alternate more cost effective use of electronic navigational systems.

Of lighthouses, there are, I believer several types and the difference usually has to do with the location of the light.

The first and most common light are those built on land, or commonly called Onshore be it on a beach, bluff, cliff, point, rock or any other geographical land feature.

The second type of light are those built not close to land but instead, Offshore, and are built in this location due to a submerged feature such as a reef, rock, shoal, or other partially or totally submerge land mass some distance from the main land.

The third type of light are those where there is a need for a lighthouse but there is not a location available to build it at the location. Often, in this case, there is a Lightship or light vessel, which is anchored near the location in which to provide the light for navigational help.

The deep and spacious harbor at Boston, led to making this the first commercial port for the thriving new colony. It was not long before the community recognized the need for night time navigational aid and in 1673 erected a beacon near the south entrance to the harbor at Point Allerton in to the village of Hull, Massachusetts.

Later, the first lighthouse, called Boston Light was built in 1716 on Little Brewster Island across Massachusetts Bay from Point Allerton. The Boston Light was destroyed in the Revolutionary War and a new light was built in 1783.

As the New World continued to be colonized by the European nations, it did not take long before there was seen a need for many more lighthouses to guide the increasing number of ships transporting cargo and passengers into the every growing colonies.

By April 1775, when the American Revolutionary War began, there had been 12 lighthouses built along the eastern seaboard.

President George Washington was presented from the US Congress their ninth act, which he signed into law on 07 August 1789.

This act of congress created the U. S. Lighthouse Establishment and provided that the states must turn over their lighthouses to the federal government. Too, this new organization would be in charge of all of the aids to navigation and would be under the responsibility of the Secretary of the Treasury.

After 1850, more than three hundred lighthoused had been built in the United States and there came to be many complaints about the construction, maintenance and management of these. Thus soon after, Congress set up a light house board to review the complaints and report its findings to Congress. From this, the US Lighthouse Board headed by US Army and US Navy engineers, then began to make changes in all aspects of their construction and management.

From this time forward, lighthouses were equipped with new Fresnel lenses, new types of fog signals and buoys, all of which improved the lighthouse operations over the entire seaboard.

Michigan has about 115 lighthouses (are all along the Great Lakes) and thus Michigan has the most lighthouses of any U.S. state.