The Ohio Historical Society will lay off 25 employees and reduce hours at 13 historic sites to cope with state budget cuts.

"We have put into action a number of cost-saving measures this year, including an upcoming seven-day furlough at the end of the month, but it's just not enough to overcome the loss of state funding," said William K. Laidlaw Jr., executive director and chief executive officer.

He said the society, which has the largest number of historical sites of any state, will use private funds to supplement state dollars to keep 18 sites open though this fiscal year, which ends June 30.

However, further cutbacks -- including site closings -- are possible after July 1 unless the society is able to restore $1.2 million in state funding in each of the next two years, Laidlaw told state legislators in a recent budget hearing.

Of the 25 employees let go, 15 are at the Ohio Historical Center in Columbus; the remainder are at other sites across the state. Forty-two employees have reduced work schedules.

These sites will have reduced hours until further notice:

Adena Mansion & Gardens, Chillicothe; Campus Martius Museum and Ohio River Museum, Marietta; Flint Ridge, near Brownsville; Fort Ancient, near Oregonia; Fort Meigs, Perrysburg; Harding Home, Marion; National Afro-American Museum & Cultural Center, Wilberforce; National Road/Zane Grey Museum, near Norwich; Piqua Historical Area, Piqua; Serpent Mound, near Peebles; Wahkeena, near Lancaster; Youngstown Historical Center of Industry & Labor; and Zoar Village, Zoar.

Hours will not be reduced at the Ohio Historical Center in Columbus, along with the Armstrong Air & Space Museum in Wapakoneta, Fort Hill near Hillsboro and Newark Earthworks in Newark and Heath.

The society previously announced that it will temporarily close most of its sites from March 28 to April 3 to save money.

Laidlaw said the organization is trying to buy time to work out agreements with local organizations across the state for daily management of 18 historic sites. The state retains ownership and ultimate control over the sites and collections. Half the society's 58 sites are jointly operated.

The society faces $750,000 in red ink in the fiscal year that ends June 30. Its work force of more than 400 a decade ago has been cut nearly in half. Officials recently cut contractual services, equipment purchases and out-of-state travel and eliminated a 2 percent, half-year raise for workers.

Additional information on sites and hours can be viewed at www.ohiohistory.org.

ajohnson@dispatch.com