The hilltop mansion at Berkeley Plantation has a sweeping view of American history, if you’re still into that sort of thing.

English colonists settled the land along the James River a year before Plymouth and held one of the earliest recorded Thanksgiving celebrations there. The three-story Georgian home, built by the Harrison family in 1726, was the birthplace of a U.S. president and a signer of the Declaration of Independence. Taps was even composed at Berkeley 150 years ago during the Civil War, when Union soldiers used it as a base.

There is, then, an abundance of history at the home. Visitors, however, aren’t so plentiful anymore.

Mirroring what’s happening to other historic house museums across the country, attendance is down 20 percent over the past five years at Berkeley Plantation, according to the national historic landmark’s private owner. The situation, he said, is bad and getting worse.

“We’re scrambling right now,” said Malcolm Jamieson, whose late father personally restored the property, about 30 miles west of Williamsburg, then opened it to public tours several decades ago. “I think about the problem all the time. But I don’t know what to do.”

Most house museums rely on admissions, gift-shop revenue and donations to cover operating expenses. A few have substantial endowments or receive government funding. But not Berkeley Plantation, where Jamieson cut his salary and has been hosting more weddings and corporate events to stay afloat.

There are hundreds — if not thousands — of house museums across the country, although nobody knows exactly how many. Virginia is particularly rife with them, given its central role in American history, from Colonial times through the Civil War.

The state has counted more than 100 homes in the commonwealth that are open to the public as historic sites and museums, and it will soon start promoting them: Gov. Robert F. McDonnell (R) has proclaimed 2013 the year of Virginia historic homes, in part to celebrate the Executive Mansion’s bicentennial but also to call attention to the state’s other house museums.

“We all know of Monticello and Mount Vernon, and they’re fabulous,” said Sarah Scarbrough, who is director of Virginia’s Executive Mansion. “But there are so many other homes in Virginia, and they’ve been struggling. The severity of the problem is alarming.”

A long decline

The issue isn’t exactly a new one for the old homes; most house museums have been reporting slides in attendance since 1976, when America turned 200 and interest in U.S. history spiked.

That year, Thomas Jefferson’s Monticello welcomed a record 671,000 visitors; in 2011, attendance at the Charlottesville-area estate was 440,000.

Stratford Hall, Gen. Robert E. Lee’s birthplace on Virginia’s Northern Neck peninsula, was toured by nearly 80,000 people in 1976, executive director Paul Reber said. In 1991, Stratford’s attendance was 51,000. Last year, it was 27,000. “It’s a pretty dramatic downward slope,” Reber said.

Economic forces are partly to blame. Tourists aren’t traveling as much because of gas prices and shrinking discretionary budgets. School systems — which send kids to historic homes to bring the past alive — aren’t funding as many field trips.

“Which is a shame,” Scarbrough said. House museums, she said, are major cultural assets that help people understand the heritage of their communities and the country, providing context, stories and rich detail about people, places and periods.

Several of Virginia’s house museums, which were once open daily, have cut back to four days, three days or even one day a week, Scarbrough said. There’s been talk that a few of them might be closing for the winter — and there’s concern that some might close their doors for good.

It wouldn’t be the first time.

Twelve years ago, Lee’s boyhood home in Alexandria was sold because the nonprofit foundation that owned it couldn’t afford its upkeep as a museum. The buyers — venture capital executive Mark Kington and his wife, Ann — turned the historic treasure into a private residence.

Carter’s Grove, a spectacular Colonial-era property on the James River, not far from Berkeley Plantation, was closed in 2003 by the Colonial Williamsburg Foundation, which had been operating it at a substantial loss. It was sold several years later to Internet entrepreneur Halsey Minor, who proceeded to neglect it. Carter’s Grove began to fall apart, to the dismay of historians, preservationists and the Colonial Williamsburg Foundation, which foreclosed on the property.

Blame historical illiteracy or apathy at your own peril; attendance at many of the Smithsonian Institution’s museums has been up again, and a film about Abraham Lincoln is among the year’s top-25-grossing movies.

Consolidate or close?

Of course, not every house museum is suffering serious attendance declines. Some aren’t declining at all: Mount Vernon Estate, Museum & Gardens, George Washington’s place in northern Virginia, welcomed more than 1 million visitors in 2011 — a 10 percent increase over 2006. Attendance is up almost 2 percent this year, according to a spokeswoman.

But they can’t all be historical rock stars like Washington, a top draw in the battle for mind share, money and visitors.

So some preservationists and historians are pushing for house museums across the country to merge their operations to find efficiencies in overhead, maintenance, marketing and administration, said Kenneth Cohen, the museum studies program coordinator at St. Mary’s College of Maryland. The idea hasn’t been warmly received.

“Institutions are generally reluctant to give up their autonomy,” Cohen said. “The result is that lots of small historic houses are teetering on failing — and closing.”

That possibility has prompted some high-profile preservationists to brainstorm a going-out-of-business plan for house museums, said Reber, the Stratford Hall executive director. “Because how do you deal with these cultural assets when they just can’t function anymore, when they decide it makes no sense to operate, because it’s too expensive, and you’re not getting enough people?”

At Stratford, the day of reckoning isn’t on the coming calendar. Even with visitation numbers well below Reber’s goal (“We should be at 50,000,” he said, “not struggling for 30,000”), the museum is hardly imperiled.

“We have a fairly large endowment,” he said, “and could survive for a long time just dawdling along.”

But status quo is bad for the business of delivering history, Reber said, and is probably another driving force behind the industry’s attendance woes.

“These places are designed to tell a story for a demographic that doesn’t exist like it did decades ago,” he said. “We still deliver our stories to visitors with a guided tour, walking through the house with them. We hit them over the head with it, because that’s the way we’ve always done it.

“But people have the Internet in front of them now and can find anything they want and create their own narrative and explore the things that interest them. We have to adapt.”

Stratford is developing a smartphone app for visitors. It will include various narratives and a trove of details on everything from architecture and furnishings to individual members of the Lee family and the stories of their slaves.

It will allow visitors to interact with the house and the history in their own way, he said, although Stratford will continue to offer guided tours, too.

A new take on history

On a recent weekday, interpreter Sandra Smith was standing outside Montpelier, James Madison’s sprawling estate at the foot of the Blue Ridge Mountains. Smith led nine visitors through the Founding Father’s house and talked about the architectural design and the furnishings and the dinner parties and the recent $25 million restoration project that brought the home back to the Madison-in-retirement era.

She talked about Dolley Madison’s sensibilities and her husband’s intellect and interests, and, of course, the Constitution and Madison’s Virginia Plan and his term as the fourth president.

Doug Smith, executive director of Montpelier’s Center for the Constitution, had joined the tour, but all he could think about was augmented reality: Montpelier recently released a free iPhone app (an Android version is landing any day now), and Smith had been playing with it on his phone, listening to audio about slave quarters and looking at high-resolution images of objects on display on the 2,650-acre property.

“But there’s so much more we want to do,” he said, noting how great it would be to be able to lift his iPhone anywhere at Montpelier and see what life used to be like there, through images and interpretive videos and other information that would be presented based on the smartphone’s exact location and orientation. “As a historic property, you want to make sure you have a high degree of authenticity and scholarship. But you can’t be scared of the technology, either.”

Visitor numbers have dropped since reaching 132,000 in 2009, the first full year after the restoration.

Stopping the attendance slide? Perhaps there’s an app for that.

“The world is changing,” Smith said.

“If you want to play in a modern, relevant space, then you have to think differently and present differently. We want to tell the best story we can to as many people as we can.”