The Old Post Office Building in downtown Washington now houses the Trump International Hotel. (Linda Davidson/The Washington Post)

As much of federal Washington remained closed during the government shutdown, a site staffed by the National Park Service that offers the best views of the city continued to run.

At the federally owned building that houses the Trump International Hotel, the historic clock tower at the top of the Old Post Office Pavilion remained open during most of the five-week shutdown. President Trump announced Friday that a deal with congressional leaders had been reached to end the shutdown at least temporarily, with a compromise to reopen the federal government for three weeks.

Rising to 315 feet, the observation tower runs daily tours from 9 a.m. to 5 p.m, according to the National Park Service website. Guests get a stunning panorama of the capital’s historic landmarks, as well as insight into the country’s current political moment. All around, visitors during the shutdown could see federal sites and tourist destinations that were shuttered or understaffed. But the clock tower remained open.

The General Services Administration leases the Old Post Office to the Trump Organization. The GSA, in a post on its website this month, said it was authorized to pay the National Park Service to keep the observation tower open, even though the Park Service’s funds lapsed during the shutdown. The GSA said the money came from the Federal Buildings Fund, which is “primarily supported by rent paid to GSA from other federal entities.”

In 1983, Congress directed the GSA to pay the National Park Service to provide visitor services at the clock tower, so the site is not tied to the status or funding of other Park Service locations. In a statement to The Washington Post on Friday, the GSA said the clock tower is one of more than 8,000 properties it manages across the country that are funded through the Federal Buildings Fund. The agency said nearly all were “operating as normal” during the shutdown.

“The Building Services account has remained funded thus far during the partial shutdown, and all bills due under that account are paid accordingly and treated the same," GSA spokeswoman Pamela A. Dixon said in the statement, issued before the deal to end the shutdown was announced. "GSA will continue to treat all properties and accounts in accordance with the law and our operating procedures.”

The GSA has previously said it can use money from the buildings fund “to operate federal facilities, as needed, until they are expended, notwithstanding a lapse in appropriations.”

The decision to keep the clock tower open was “unrelated to the facility’s tenant,” the GSA has said.

The majority of national parks were closed during the shutdown, according to the National Park Service. In a statement to The Post, the Park Service said it staffs the Old Post Office under an agreement with the GSA, which owns the building and pays for Park Service staff.

Of 418 national parks, about 80 — or about 19 percent — remained open, according to the Park Service. The operating sites were funded using recreation fee revenue, but the clock tower is not funded this way.

The Trump Organization did not respond to a request for comment.

The continued operations of the clock tower raised questions about why it remained open while many other federal sites were closed, and whether the building received special treatment because its tenant is the president’s company.

This month, the advocacy group Citizens for Responsibility and Ethics in Washington (CREW) sent a public-records request to the GSA, asking for information about the funding for the tower’s continued operations. CREW is seeking documents from the GSA, the White House, the National Park Service and the Trump Organization. CREW told The Post it has yet to receive a response to its records request.

CREW’s executive director, Noah Bookbinder, said the tower’s ongoing operation seemed particularity problematic, because hundreds of thousands of federal employees and contractors faced financial hardship and key public services were disrupted during the shutdown.

“It certainly looks like this is open because it is located at the site of the president’s business," he said. “People may have felt pressure to give preferential treatment, even if nobody said anything.”

The Associated Press reported earlier this month on the clock tower remaining open.

The Trump Organization won the lease to the building several years before Trump was elected president. But according to a recent report from the GSA’s inspector general, the agency “ignored” concerns that the lease might violate the Constitution by allowing his company to keep it after Trump took office.

The clock tower is one of the tallest structures in the city. Since the Washington Monument is turning away visitors until the spring so it can update its elevator, the clock tower offers an unrivaled view of the nation’s capital.