Several criteria are used to determine whether a property is historic. They include:
Properties greater than or equal to 50 years old are considered historic.
Special Architectural Significance:
Some properties less than 50 years old are considered historic because they possess special architectural significance; for example, they might be the first of a type built; be an exceptionally good example of a particular method of construction or style; or represent the work of a noted architect or master builder.
Some properties less than 50 years old are considered historic because of their association to significant events or persons; for example, properties associated with the Civil Rights movement are now being considered historic at the national level as well as the state and local levels. Another example would be a President's home that is not 50 years old but would certainly be considered historic.