FREDERICKSBURG, Va. – Chatham Manor, the elegant 241-year-old Georgian house that served as a Union headquarters during the Civil War, remains a must-see stop on tours of Fredericksburg and Spotsylvania National Military Park.

But the grounds are not as they once were. The gardens are overgrown, and the greenhouse has broken windows and rotting wood frames.

The park’s superintendent, Russell Smith, noted that the family who occupied the home in the 1920s “had nine or 10 gardeners. I have, like, half a gardener.”

After more than a decade of scrimping and deferring maintenance and construction projects – and absorbing a 6 percent budget cut in the past two years – the signs of strain are beginning to surface at national parks across the country.

The 469-mile Blue Ridge Parkway, which curves along the spine of the easternmost range of the Appalachian Mountains in Virginia and North Carolina, has a $385 million backlog of projects.

For the past three years, New Mexico’s Bandelier National Monument has lacked the money to hire a specialist to protect its archaeological ruins.

Jonathan Jarvis, the National Park Service director, said in an interview that his employees have been “entrepreneurial” in devising ways to cope with rising costs on a fixed budget.

“But we’re kind of running out of ideas at some point here,” Jarvis said. For years, the Park Service has supported day-to-day operations by taking money from its maintenance and land acquisition budget, he said. “The challenge is, we’re robbing Peter to pay Paul.”

Annual attendance at national parks has remained about the same, although visits through July this year total 201 million, up 1.5 percent from 2011.

Park managers say they are alarmed at the prospect of both next year’s budget and a possible 8 percent across-the-board cut if negotiators fail to reach a budget deal by January. The president’s fiscal 2013 budget proposal – which was largely adopted by the House Appropriations Committee – would cut 218 full-time jobs, or 763 seasonal employees.

Phil Francis, superintendent of the Blue Ridge Parkway, said he’s lost a third of his permanent maintenance crew in the past 11 years. Staff have gotten “a few visitor complaints” about conditions in the park.

“Of course we know these things,” he said. “It’s a challenge.”

Thomas Kiernan, president of the National Parks Conservation Association, said policymakers face a critical decision as the park system approaches its 100th anniversary in 2016.

A major influx of funds could mobilize public support for the system, he argued. Without it, he said, conditions at the parks will continue deteriorating and visits could drop.

“It’s clear that inadequate federal funding is the No. 1 threat to the future of the national parks and the national park idea,” Kiernan said. “We’re at a crossroads of historic importance here.”

Of the 397 park units, 158 have “friends groups” that help raise private funds.

The congressionally chartered National Park Foundation has raised up to $150 million annually for parks in concert with those organizations in recent years, and it hopes to help expand them to 200 by 2016.

But that’s a fraction of the system’s $2.6 billion annual budget.