The Filene Center at Wolf Trap. (Tracy A Woodward/The Washington Post)

An inspector general’s report released Thursday questions the National Park Service’s financial support of the Wolf Trap Foundation for the Performing Arts and the long-standing practice of giving free tickets to government officials.

The report from the Interior Department’s inspector general notes that the nonprofit that helps fund performing arts programming at the park, which was established in 1966 on 130 acres of federal land in Fairfax County, “still receives federal funding even though it appears to be self-sufficient.” The report also raises concerns about the finances of the foundation, which is a separate entity from the park.

In 2016, the report noted, the Park Service allocated $4.2 million to the park and awarded the foundation $594,000 to hire stagehands and “theatrical personnel,” although the foundation netted $2.7 million, employs more than 90 people and pays its executive director $580,300 a year. The foundation has also collected $2 million from leases on cellphone towers since 1995, according to the report.

“The current agreement states that the foundation should be self-supporting and that it should gradually stop receiving federal support as soon as it is able to handle financial obligations on its own,” the report said.

The report questioned why the secretary of the interior receives eight free tickets for each performance, a practice “since at least the late 1970s.” As early as 1979, an inspector general concluded the department should “forbid free or discounted tickets to Department personnel,” according to the report.

“For the upcoming 2018 season, the average price of eight tickets is valued at $543,” it said. “According to the Park’s website, the venue hosts more than 80 shows each year, placing the total annual value of the tickets given to the secretary at more than $43,000.”

The Interior Department referred questions to the Park Service, which is an agency of the department. In a statement, Park Service spokeswoman Jenny Anzelmo-Sarles called the report a “helpful tool.”

“While other national parks host performing arts events, in contrast to Wolf Trap, they are generally secondary to the purpose of those parks,” the statement said. “The programmatic expertise, fundraising and visitor services provided by the Foundation are crucial to our ability to provide visitors with exceptional, one-of-a-kind experiences.”

Anzelmo-Sarles and Erick Hoffman, the Wolf Trap Foundation’s communications director, said the Park Service addressed some of the concerns in July after reviewing a draft of the report.

A response to the draft said comparing Wolf Trap to other parks was “misleading,” as it should be compared to venues like the Kennedy Center, whose director “is compensated at a rate nearly double that of the Foundation’s CEO.” It also said the Park Service is reviewing the practice of giving tickets to the interior secretary.

“The park is a live performing arts venue operating within a highly competitive business environment, which is substantially different from other national parks and their partners,” the response said. “Therefore, it would be more accurate to compare the foundation with similar performing arts venues and performing arts organizations.”

The report comes as the foundation and the Park Service negotiate a new cooperative agreement. The existing 20-year agreement expires Oct. 1.