The downtown core has an Historic Preservation Overlay District, defined by the FHMC. These are areas intended to preserve structures, buildings, appurtenances, and places that are of basic and vital importance for the development of the culture, because of their association with history; because of their unique architectural style and scale, including color, proportions, form, and architectural details; or because of their being a part of or related to a square, park, or area of cultural, historical, or architectural importance to Friday Harbor.