Interstate Highway System

Final List of Nationally and Exceptionally Significant Features of the Federal Interstate Highway System

As the Dwight D. Eisenhower National System of Interstate and Defense Highways (Interstate Highway System) approached the fifty-year anniversary on June 29, 2006, large sections of the Interstate System would have achieved the mark at which resources are often evaluated for historic significance. In order to address the volume of administrative work this could foster, the Advisory Council on Historic Preservation adopted the Section 106 Exemption Regarding Effects to the Interstate Highway System on March 10, 2005. To learn more, visit Streamlining Recommendations for Historic Preservation.

This exemption effectively excludes the majority of the 46,700-mile Interstate System from consideration as a historic property under Section 106 of the National Historic Preservation Act (NHPA). In addition, the recently enacted Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) re-authorization legislation (Public Law 109-59, Aug. 10, 2005) includes a provision (Section 6007) that exempts the bulk of the Interstate Highway System from consideration as a historic property under Section 4(f) of the Department of Transportation Act. With these two exemptions in place, Federal agencies are no longer required to consider the vast majority of the Interstate Highway System as historic property under Section 106 and Section 4(f) requirements. Excluded from these respective exemptions are elements of the Interstate System that are exceptional in some way or meet a national level of significance under the criteria for the National Register of Historic Places. The final list above identifies those elements that are not to be covered by the exemptions discussed above and will therefore continue to be subject to consideration under the Section 106 and Section 4(f) processes.

Historic Mt. Baker Ridge Tunnels on I-90
Photo courtesy of Washington DOT

Listing of State Archival Materials Pertaining to the Interstate Highway System
View this list of archival materials for each state, including source or responsible party, and specific contact information.

For additional information, contact MaryAnn Naber, Federal Preservation Officer, FHWA Office of Project Development and Environmental Review, at maryann.naber@dot.gov.

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