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Survey Historic Places

Surveys of historic resources are important to the citizens of Oregon because they help us identify significant buildings, structures, objects, sites, and districts, and focus our limited resources on their preservation.

Mandated by the National Historic Preservation Act (NHPA) of 1966, and Amendments, surveys are carried out and supported by the State Historic Preservation Office (SHPO), as well as by historic preservation professionals on contract to other state agencies, local governments, and businesses.

A survey is the process of gathering and recording information about historic resources, identifying those that may be historically significant locally, statewide, or nationally, and updating existing information on previously documented or officially designated properties. Once recorded, the data generated are added to the statewide inventory maintained by the SHPO and on city or county inventories maintained by local jurisdictions. Conducting surveys and creating an inventory of resources are usually the first steps leading to local recognition and preservation of those resources most important to our state and local heritage.

​Built Environment

  • Reconnaissance Level Survey: The Reconnaissance Level Survey (RLS) is designed as a “first-look" at a broad group historic resources and records basic information that is collected from the exterior of a building only, such as address, height, siding and building materials, architectural style, and potential eligibility for listing in the National Register either individually or as a contributing resource to a historic district. Because the evaluations are based physical characteristics, and not supported by contextual research, RLS can identify properties that do not meet the baseline eligibility requirements of age and integrity. Evaluations of “eligible" should be considered preliminary until further research is conducted, such as through the ILS.
  • Intensive Level Survey: The Intensive Level Survey (ILS) is a detailed look at a single resource that collects detailed physical information and research data about the property's history. Information collected through an ILS can provide a solid basis for more reliable National Register eligibility evaluations. To that end, the ILS includes information of use to future researchers, such as the methodology employed, difficulties encountered or limitations that restricted research (such as a lack of interior access), where useful information was or was not found, and what areas of further research may yield useful information.
  • Regulatory Compliance Survey: Surveys conducted within the context of a regulatory compliance effort, such as Section 106 of the National Historic Preservation Act (NHPA) or Oregon Revised Statute (ORS) 358.653, are conducted according to the standards and guidelines of those regulatory programs. Because of the unique nature of these types of surveys, the depth and nature of research and documentation varies according to a number of project-specific factors. To determine the suitable scope of work for these, contact the cultural resources staff assigned to the project at the Lead Federal Agency, the State agency conducting the project, or the SHPO Regulatory Compliance Program Coordinator for built resources.

Archaeological Investigations

The purpose of archaeological investigations is to locate and protect archaeological sites significant to local, state, regional, and national history. It is important that all research efforts are adequately documented so that future preservation and interpretation projects can benefit from previous work. SHPO Guidelines (both Field and Report Guidelines) provide a framework for documenting the results of all archaeological investigations. There is also a permit process that may need to occur for archaeological investigations.

Please visit Archaeological Investigations to see that criteria and process.

Here are some of the ways that information from a survey can be used:
  • ​Nomination of individual properties and historic districts to the National Register of Historic Places.
  • Inform decision-making regarding project planning, policy development, or individual preservation efforts.
  • Assist to design tools for community education and planning, interpretive signage, community presentations walking, biking, and digital tours.
  • Used to meet the needs of those completing federal Section 106 and 4F documentation, and state and local agencies complying with state land-use laws.
  • Inclusion in the Oregon Statewide Inventory accessed through the Historic Statewide Database maintained by the Oregon State Historic Preservation Office for research purposes.

The State Historic Preservation Office (SHPO) maintains the Oregon Statewide Inventory, the collection of all information about all built properties for which the SHPO has received physical and/or historical information. While the Statewide Inventory does include the most recent evaluation for eligibility for listing in the National Register of Historic Places, inclusion in the Statewide Inventory is not an official designation of any kind. The Inventory will indicate if a property has been officially designated by listing in the National Register of Historic Places, or been officially determined to be eligible for listing by the National Park Service.

The inventory is accessed through the online Historic Sites Database, available at

Contact the SHPO to see if additional information is available beyond what is found in the online database.

Submit information about historic places!

Please provide any and all information and documentation you can by visiting The information will be added to the Oregon Historic Sites Database and may be used to designate properties to the National Register of Historic Places in the future. For information about what to submit, contact Jason Allen at 503-986-0579.

See Heritage Engagement Tools for current survey intiatives!


Built Environment Survey:

(503) 986-0690

Archaeology Survey:

Josh Henderson
(971) 718-2846

Additional Resources