A new analysis by The Washington Post has found that President Donald Trump's planned "triumphal arch" in Washington, D.C., would cast shadows on Arlington National Cemetery — one of the most revered landmarks in the USA — for most of the year. The cemetery, administered by the U.S. Army, is the final resting place of more than 400,000 soldiers, veterans, and their families.

The arch is one of several projects Trump is pushing forward, alongside his plans for a White House ballroom and his efforts to put his name on buildings. Inspired by the Arc de Triomphe in Paris and similar monuments, the structure is planned for the site of Memorial Circle, across the Potomac River from the Lincoln Memorial and near the entrance to Arlington Cemetery. Trump has proposed a height of 250 feet — taller than the Arc de Triomphe, which is about 164 feet high, and more than twice the height of the nearby Lincoln Memorial, which stands at approximately 99 feet. Critics warn that the planned height would dwarf the rest of the city's buildings and disrupt some of its iconic views.

On Tuesday morning, The Washington Post released an extensive analysis on the arch's potential impact on the nearby cemetery, using a "true-to-scale digital 3D model." The report concluded that the structure would cast a new shadow over the area on most days of the year and would also affect other landmarks across the city.

"Over the course of a year, the shadow of the triumphal arch would touch burial sites in Arlington National Cemetery on 284 days," reported the newspaper. According to the model, the shadow would temporarily cover John F. Kennedy's eternal flame — which has burned at the president's grave since his state funeral in 1963 — on 18 days, cast a shadow on the former president's memorial on 50 days, and darken the Military Women's Memorial, which honors women who served in the U.S. armed forces, on 109 days.

These values reflect basic solar geometry: in the winter months, the sun stands lower in the sky, and shadows cast by tall structures stretch to their longest extent of the year. The analysis also found that the shadow would move over the graves of veterans and their relatives from the Vietnam War, the Korean War, World War II, World War I, the Spanish-American War, and the Civil War, and would darken the gravestones of formerly enslaved people. In total, The Post determined that the shadow would pass over more than 75,000 graves. On most days, the shadow would recede from the grounds by the time the cemetery opens at 8 a.m., but on 26 days, it would persist beyond that time, according to the model.

Washington's monumental core is based on Pierre L'Enfant's 1791 plan for the federal capital, which was later further developed by the McMillan Commission's 1901–1902 plan; both treated the open spaces and sightlines between landmarks as central to the city's design. "The original designers understood that the open space between significant structures was as important as the landmarks themselves," said Neil Flanagan, an architect and historian currently writing a book about Washington's design, to The Post.

Paul Eaton, a retired major general of the U.S. Army whose parents are buried in the cemetery, told the newspaper that the idea of the arch casting shadows on the graves of veterans would be "a sacrilege."

The findings contradict the Interior Department's own claim that the arch would cast only a small amount of shadow on the cemetery for less than two weeks per year. When the agency provided a copy of the report containing these claims, The Post found that it "did not explain the methodologies used."

When asked for comment on the findings, the White House largely avoided the question. A spokesman told The Post only that the arch would "enhance the visitor experience" at Arlington and become "one of the most iconic landmarks not only in Washington, D.C., but worldwide." As of the publication of the analysis, the discrepancy between The Post's model — 284 days — and the department's estimate of fewer than 14 days remained unresolved.