HELENA, Mont. — The managers of Utah's Zion National Park missed an opportunity when 10 spectacular acres of privately owned land within the park's boundaries came onto the market.

The managers wanted Zion to buy up the property and protect it from further development because of its world-class view of the park's awesome, 3,800-foot red rock cliffs. But the park didn't have the money.

A California couple eventually purchased the land, expanded an old tavern on the site and use it for spiritual retreats.

"Now there's a large structure with lights that people would see as they drive the road," said Zion Superintendent Jock Whitworth.

Within the 84-million-acre national park system are some 5.4 million acres of private parcels, an area nearly as big as New Hampshire. They include wetlands popular for birdwatching at Acadia National Park in Maine, the site of a Civil War hospital at Gettysburg National Military Park in Pennsylvania and Indian cultural sites at Big Bend National Park in Texas.

Many of these parcels have been held for generations by people who owned the land before Congress created the parks.

The Park Service has identified about a third of the private land for acquisition. But in fiscal year 2007, the agency was allocated $24.6 million for buying the property. That is little more than 1 percent of the $2 billion or so the Park Service says would be needed to purchase all the land it wants.

"We ought to be finishing what we started, and we're not doing it," said Paul Pritchard, founder of the National Park Trust, a private organization.

The National Park Service has on its wish list 11,613 tracts encompassing 1.8 million acres. The $24.6 million allocated is down from a 10-year high of nearly $139 million in 1999.

National Park Service spokesman Jeff Olson said the Bush administration has focused more on managing the land it already controls than on acquiring more.

"The dollars have steadily fallen off because we are in deficit, because we are funding a two-front war, because there are a host of other spending priorities that compete," said Alan Front, vice president for the Trust for Public Land.

But he warned that unless the Park Service acquires the private land within the parks' boundaries, "there is a real and pressing threat that inappropriate development will mar the landscape that people are flocking to for respite and retreat."

Chuck Cushman of the American Land Rights Association, formed in 1978 to represent owners of property within parks, said it is just as well the Park Service is short of money.