Preservationists who have for years criticized the Army’s stewardship of Arlington National Cemetery are lauding the long-awaited listing of the country’s premier burial ground on the National Register of Historic Places.

The appointment to the National Park Service’s official list of historic sites last month comes as the cemetery is celebrating its 150th anniversary, and it follows a lengthy application process that historians and conservationists said should have happened years ago.

The cemetery came under fire after it announced plans in 2007 to replace the Tomb of the Unknowns because of the appearance of at least two long, visible cracks. The cemetery backed off its plan to replace the historic tomb, a 48-ton marble monument that is the site of the changing of the guard, and instead has worked to repair the cracks. But the way it has proceeded with some of those repairs also angered preservationists.

Now that the National Park Service has officially listed the cemetery — where presidents, Supreme Court justices and veterans from every U.S. conflict are buried — the designation will ensure that the cemetery’s historic assets will be vigorously maintained and safeguarded, officials said.

“It should have been on the list long ago,” said Rob Nieweg, field director of the National Trust for Historic Preservation’s Washington field office. “But now we can rest assured that a place which is officially considered historic will be treated better and in accordance with its status.”

Jack E. Lechner Jr., Arlington’s deputy superintendent, said in a statement: “We are pleased that it’s now listed among the nation’s historic places worthy of preservation so that future generations can continue to honor, remember and explore these hallowed grounds.”

Arlington House, the former home of Robert E. Lee that is at the top of the hill overlooking the cemetery, has been on the national register since 1966. But the fact that the cemetery was not listed came as a surprise to the leadership team that was installed by senior Army officials in 2010 after a scandal involving misplaced remains. In addition to ensuring better oversight of the cemetery’s burial procedures, officials moved quickly to have the cemetery designated as a historic site.

That effort received renewed attention after two large decorative, marble urns that had been part of the cemetery’s Memorial Amphitheater turned up for sale at an Alexandria auction house in 2011. Cemetery officials said they didn’t know how the urns got into private hands, which would have probably been prohibited if the cemetery had been listed on the register at the time.

The urns were returned to the Army. But their appearance on the auction block catalogue touched off another round of criticism from Nieweg and others who questioned the Army’s ability to protect the cemetery’s many historic artifacts.

But this week, Nieweg praised the cemetery’s efforts, saying it is taking care to continue to repair the cracks in the tomb.

“The cemetery has employed experts and has been open to outside advice, which is critical,” he said.

In announcing the historic designation last month, National Park Service Director Jonathan B. Jarvis said that “for 150 years, Arlington National Cemetery has defined how America commemorates and memorializes those who have fought for the freedom of its citizens.”