Look at the figures from one angle, and the majority of land - about 80 percent - within the 6,000-acre boundary of the Gettysburg National Military Park is owned, and therefore protected, by the federal government.

From a different perspective, however, that means one out of every five acres within those same boundaries is considered private property without conservation easements and therefore subject to potential development.

Given the conclusions of a report released Tuesday by the National Parks Conservation Association, preservationists are seeing things from the latter position.

The report, titled America's Heritage: For Sale, explores the land-acquisition needs of the nation's parks and highlights Gettysburg as a prime example of a park threatened by incompatible development.

It would take $3.6 million to purchase four parcels of land that are for sale and at risk for development within the Gettysburg National Military Park, according to the report.

That land - 119 acres altogether - is not the whole of Gettysburg's land-acquisition needs but represents the priorities identified by the Park Service, said Cinda Waldbuesser, the conservation association's Pennsylvania program manager.

"Gettysburg is a great example of the needs throughout the system," Waldbuesser said. "All of this land that the Park Service doesn't own and isn't able to protect is really at risk of being developed."

On those 119 acres are battle-era structures, cultural landscapes and the site of a battlefield hospital, according to the report.

Because those parcels are "not yet under contract," Waldbuesser said she could not identify their specific locations.

"I think it is important to see them as just a small example of the total amount of land within the boundary of Gettysburg that is not owned by the (National Park Service) and is at risk of inappropriate development," she said.

Compared to other parks, Gettysburg is at the "high end" of parks its age in terms of acreage not owned by the Park Service, Waldbuesser said.

Across the nation, 1.8 million acres of land within national parks are most threatened by development, the report says. To purchase that land would cost the government $1.9 billion.

"Once lost to incompatible development, private inholdings can disrupt or destroy park views, undermine the experience of visitors, and often diminish air and water quality while simultaneously increasing light and noise pollution," the report reads.

In the report, blame is placed on Congress and presidential administrations for not providing adequate funding for the Land and Water Conservation Fund - established by Congress in 1964 to conserve outdoor resources. The federal fund is meant to serve as the primary source of funding for land-acquisition needs of national parks.

During the past decade, that funding has decreased by more than $100 million, according to the report.

That trend holds true in Gettysburg, where the federal government has not funded land acquisition within the Gettysburg National Military Park for the past eight years.

The last time the Park Service received land-acquisition funds was in 2001, when the federal government committed more than $5.98 million.

However, the president's proposed 2009 budget includes $2.2 million for land acquisition within the park.

In its report, the conservation association makes three recommendations, including that at least $100 million be appropriated in the 2009 Land and Water Conservation Fund to support land-acquisition needs.

The group also states the 1.8 million acres of land for sale within park boundaries should be purchased by the government by 2016 - the 100-year anniversary of the creation of the National Park Service.

Finally, the report suggests that Congress ask the Park Service to produce a list of all its priority inholdings to be acquired between now and 2016 from willing sellers and provide an update on inholdings faced with immediate development threats.