HARTFORD, Conn. — Mark Twain, Edith Wharton and other boldfaced names among the dead have something in common with living Americans in these hard financial times:

Their homes are in jeopardy.

For scores of historic house museums, simply keeping the lights on has become a challenge. The Mount, Wharton's home in Lenox, Mass., is trying to stave off foreclosure with a feverish fundraising campaign. The Twain House in Hartford can't even afford to buy energy-saving light bulbs that would slash its electric bill.

Experts say this summer may make or break some sites, many of which already have cut their hours and staff and are struggling for donations in today's troubled economy.

"The jury's really still out on how summer visitation will be, how people will respond to gas prices and what it will mean for us," said Susan Wissler, acting president of The Mount, which needs $6 million by Oct. 31 to avoid foreclosure.

The Twain House and Museum is in similar straits, trying to repay a $4.9 million bank loan from earlier expansions and meet its $2.9 million yearly budget.

They already cut two-thirds of the staff and made other reductions, but had barely enough money to pay three weeks' worth of bills before recent publicity generated a spate of donations.

Many house museums, especially smaller sites, get little or no government help. Tourist dollars, donations, interest earned on endowment funds and corporate gifts — all highly dependent on the economy — help keep the doors open.

The National Trust for Historic Preservation estimates there are between 9,000 and 10,000 historic home museums nationwide.

Some, like the Twain and Wharton homes, are established landmarks run by nonprofit groups. Thousands of others are homesteads of early settlers, birthplaces of noteworthy Americans or other modest sites run by local historical societies and volunteers.

"Many of them are operating on a shoestring, but they're very important to their communities and people put in a lot of volunteer time and effort just to keep them going," said Richard Moe, president of the National Trust for Historic Preservation.

"It's a complex financial situation out there for a lot of museums, and there's no question that house museums are facing some unique challenges these days," he said.

Even government ownership isn't a guarantee of security. As states and municipalities cut their budgets, many have reduced the hours at the historic homes they operate or turned the sites over to private groups.

The tiny northern Vermont birthplace of President Chester A. Arthur reduced its hours from five days weekly to two this summer to reflect state budget cuts.

The Ohio Historical Society this spring increased admission fees for the first time in four years. It also cut jobs and sliced hours at many sites, including the Marion home where Warren G. Harding launched his 1920 presidential campaign.

For the Twain and Wharton houses, yesterday's improvement projects are today's financial burden.

Jeffrey Nichols, the Twain House and Museum's executive director since April, says officials now recognize that a $19 million visitor center that opened in 2003 was too ambitious and costly.

The gingerbread Gothic home was built in 1874 by the author and humorist who, coincidentally, often struggled with debt and had to sell the home in 1903.

"The museum saw a great opportunity to expand and to better preserve and spread Mark Twain's legacy, but in retrospect, it did overreach," Nichols said.

In that regard, the Twain House is like private homes throughout America where residents expanded during heady economic times or used home equity credit lines, subprime mortgages and private loans they now struggle to repay.

The Mount finds itself in similar straits.

The restoration of its mansion and gardens is lauded in architectural and historical circles, and its 2005 purchase of Wharton's personal library for $2.6 million was even singled out by first lady Laura Bush for special praise.

But the seller is British, so payments skyrocketed as the British pound's value has pummeled that of the dollar.

Wharton designed and built the 1902 home, where she later finished "The House of Mirth" and got the inspiration for "Ethan Frome." She lived there until 1910, when her marriage collapsed and she moved to France.

Wissler said the organization that runs the home reduced its staff, negotiated fixed rates on some utility bills and is working with the bank to restructure the loan terms.

"We've expanded our facilities very carefully. What's occurring now is a timing issue as much as anything," she said.