The emblems of Cranberry's prosperity can be seen in just about every direction from the 135-year-old stone-and-timber farmhouse tucked away in the township's northeast corner, on one of its original roads. Houses, pavement and commercial buildings have bloomed on Denton Powell's horizon like so many dandelions in spring.

The 73-year-old dairy farmer doesn't complain about what neighboring landowners have chosen to do with their little slices of heaven over the years, but, for his part, he's determined that his 71-acre dairy farm on Goehring Road doesn't go the way of the horse and buggy.

"Whatever anyone else does is their business. But I'm a farmer. I like the land. I don't want anything happening to my farm," said Mr. Powell, who is unmarried, has no children and whose farm is one of two working farms left in Cranberry.

He's worked hard in recent months to protect his land, securing the backing of Cranberry officials in his effort to have his farm included in an agricultural security district. Now he's working with the state and Butler County to sell the development rights to his property, guaranteeing that the land can never be used for anything but farming, regardless of who owns it.

His efforts and the support of the community earned his farm a spot on the list of the region's top 10 historic preservation opportunities. The list, released Monday, was compiled by the Young Preservationists Association of Pittsburgh, a group that incorporated in 2002 with the motto "Giving Life to History."

Dan Holland, founder of the preservationists association and chairman of its board, said the Powell farm was the first working farm to make it onto the group's endangered list.

"It's the threat factor that's coming into play. Farms throughout our region are in danger of being lost forever. And, in this case, there's a great plan for preservation that's in the works. Selecting the Denton Powell Farm serves the symbolic purpose that farms in our region can be saved," Mr. Holland said.

The key requirement for making it onto the top 10 list is that the historic site be endangered, but it also must have potential for survival.

"We're not just trying to call attention to endangered sites. We need to have a viable win in the making," Mr. Holland said, noting that the ultimate purpose of the list is awareness.

Other sites to make the list this year include the Vandergrift business district, First Presbyterian Church in Braddock, Graceton Coke Ovens in Indiana County and the McCook Mansion in Shadyside.

His group is open to anyone of any age who "supports the next generation for historical sites," he said, but the target group is between the ages of 21 and 45. The group has a 15-member board and a 23-member advisory committee.

Cranberry Planning Director Michelle Mixell nominated the farm for the top 10 list after she became involved in helping Mr. Powell get his land included in the agricultural security district last year.

Participation in an agricultural district effectively blocks local governments from enacting any ordinance that deems farm property a nuisance, such as restricting hours of operation for farm equipment or setting limits on where manure can be spread. Mr. Powell had to join an agricultural district in Adams because Cranberry doesn't have one and can't, because state law requires a minimum of 250 acres of farmland to establish a district. The law allows a farmer to join a district in another municipality if both local governments approve.

"His farm is one of only two working farms that remain in Cranberry Township. The farmhouse is original to the property, and it was built from stone and timber that was collected from the property itself. It's just beautiful," Ms. Mixell said. The farmhouse dates to 1871.

Mr. Powell, who was named by the Butler County Conservation District as 1999 Farmer of the Year, works the land himself and maintains a herd of 60 dairy cattle. His father, William, bought the property in 1951 when he moved to Cranberry from the Beaver Valley. He said it had been in the Hendrickson family before his and that it had been in continuous operation for 135 years.

Ms. Mixell said she had great respect for Mr. Powell's concern for the land.

"With development pressure knocking at his door every day, he had the determination and the land ethic to try to make this happen," she said, referring to his ongoing effort to sell the conservation easement to his property.

Each year, the Butler County Farmland Preservation Board accepts applications in January from farmers interested in preserving their farmland for posterity. Ron Fodor, director of the Butler County Conservation District, manages the program.

He said the number of easements purchased each year depended on the amount of money the board has banked. Butler County commissioners donate about $125,000 a year and the state contributes. This year, the fund has about $2 million. Mr. Fodor said almost every one of the county's 33 townships had at least one working farm, and that some had more than a dozen. About 20 farmers a year apply to participate in the conservation easement program.

Once a farmer sells his conservation easement, he has given up all rights forever to develop the land. Many farmers are hesitant to attach such a restriction to their land deed in perpetuity. Mr. Fodor said the average price for conservation easements was $3,000 an acre in Butler County, and the cap that will be paid by the program was $10,000 an acre.

To put it in context, Cranberry Assistant Manager Dan Santoro said raw land in Cranberry can yield $20,000 to $30,000 an acre.

"You have to really believe in farming and really want to preserve the land to be in this program," Mr. Fodor said.

He said 21 farmers applied for participation this year, many of whom have applied before. He said each property is screened for soil quality to ensure that it can continue to be farmed, and it is evaluated in terms of development pressure.

He said his board was in the process of conducting easement appraisals on three farms, including Mr. Powell's.

"His soil quality was pretty high and he certainly has lots of development pressure," Mr. Fodor said.

After the appraisal, an offer will be made to Mr. Powell. If he accepts, the deal will be transferred to the state Department of Agriculture for approval.

Last year, the farmland preservation board had about $700,000 to spend, and easements were purchased for three farms. The program has been in effect about 10 years, Mr. Fodor said, and a total of 29 easements have been purchased. In addition to Mr. Powell's, two other farm easements are being considered for purchase this year in Connoquenessing Township and Winfield.

Jim Kennedy, a Butler County commissioner and dairy farmer, said he was proud of the county's farmland preservation effort and was particularly happy to see that effort extending to Cranberry, one of the county's most bustling communities.

"We've got a real good push going to move our farms into the next generation. It's the right thing to do," he said.

Mr. Santoro said Cranberry supported Mr. Powell and other farmers who are interested in preserving farms and green space in general.

"Our township supervisors respect this kind of commitment to the land. The board sees preservation of open space and farmland as an important and worthy thing that we want to accommodate," he said.