Lighthouses were built in an assortment of architectural types that took into consideration the weather, location and amount of ocean traffic.
Round and Conical
Round lighthouses were most commonly built of brick, sometimes covered with some form of metal during original constructions. Materials and knowledge changed leading to the implementation of cast iron plating over a steel skeleton. Round lighthouses were built in large scale and smaller scales depending on the needs of the area. South Manitou Island, Big Sable Point and Manistee Pierhead are all round lighthouses.
Conical lighthouses are similar in construction to round lighthouse but differ in the fact that they possess a wide base and narrow as they reach the birdcage (light assembly room). There is often a small building at the base for entry. Point Iroquois and Tawas Point are conical lighthouses.
Schoolhouse and Square
Schoolhouse lighthouses earned their name from the similarity to old schoolhouses. They were often of brick construction with an integrated tower that houses the light assembly such as Grand Island North, Harbor Point and Copper Point. The "schoolhouse" provided a dwelling for the lightkeeper as part of the benefits of the job. Occasionally, a schoolhouse lighthouse would be constructed with wood as with Old Mission Point, a simplistic design frequently found in the Great Lakes area.
Square or integral light houses are a single building that hosts the tower and the dwelling in a square-shaped design. Sometimes the dwellings were constructed in a duplex fashion in order to house two lightkeepers with families. Big Bay Point and Watch Hill Lighthouse are both of square architecture.
Skeletal
Skeletal lighthouses were of the most basic of design. They were created simply to perform their intended function: a steel structure holding a light assembly. They offer no protection from the elements and do not provide living space. South Fox Island and Whitefish Point present traditional skeletal lighthouses.
Octagonal
Rarely, someone would decide to build a lighthouse to meet an individual's demands such as the one located at Tybee Island. These lighthouses would feature a recurring octagonal theme with a dwelling either attached or nearby the base. They were constructed to a towering 100 feet and mostly on shore. These atypical lighthouses were usually owned by an individual not by a county, state or service.