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 Mount 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 expansions and meet its $2.9 million yearly budget.

They 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.

But 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 National Trust for Historic Preservation estimates there are 9,000 to 10,000 historic home museums nationwide.

For the Twain House, yesterday's improvement projects are today's financial burden.

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

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.