In an historic district, buildings are designated as either contributing or non-contributing.
Contributing resources date from the historic period of significance established for the district. They contribute to the significance and character of the district through their historical associations and/or architectural values.
Non-contributing resources are those that, due to date of construction, alterations, or other factors, do not contribute to the district’s historic significance or character. The zoning regulations that apply in a historic district generally differ for contributing and non contributing properties.
Additional information can be obtained from the City of Portland’s Historic District Website.