National Park Service says proposed Triumphal Arch would adversely affect nearly 40 historic sites in Washington, D.C.

The National Park Service has found that President Donald Trump’s proposed Triumphal Arch would “adversely affect” historic sites across Washington, D.C., according to information posted by the agency as part of a required historic preservation review process. The Park Service said the assessment identified nearly 40 locations in the District that could be affected, after it reopened public comment to solicit additional input from outside groups.

The agency’s posting referenced the review under Section 106 of the National Historic Preservation Act, a federal requirement that seeks to account for impacts of federal undertakings on properties listed in or eligible for the National Register of Historic Places. In this case, the Park Service used the Section 106 framework to assess how the proposed arch’s effects would extend beyond the immediate footprint and into the surrounding historic environment.

The Hill reported that the Park Service asked outside groups to comment by last Thursday after restarting the public comment period tied to the assessment. The reopened comment window and posted list are intended to support the agency’s compliance with Section 106 procedures before the assessment process moves to additional steps with reviewing parties.

Among the locations identified in the Park Service’s list are major historic sites in the nation’s capital. The assessment describes an adverse effect finding rather than a determination of no historic impact, a distinction that can affect what mitigation, consultation, or redesign options agencies consider as the project proceeds.

The process is expected to continue through consultation and review, with the public record used to inform how the federal government weighs the project’s impacts on historic properties. Under Section 106, the outcome can require additional measures to reduce harm or further documentation of why particular actions would still be acceptable under the law’s consultation standards.

The Hill’s report did not indicate that the Park Service has issued a final decision approving or rejecting the arch, but the agency’s adverse effect finding places the proposal in a more procedurally demanding category for historic preservation compliance. As the comment and consultation process continues, additional agency determinations could affect the timing and scope of any subsequent permitting or approvals.