To make the registry, a farm has to have been in the same family for at least 100 years and must be signed up by the owner.
In Pennsylvania, one of the 13 original colonies, 100 years is practically nothing. Numerous farms in the southeastern quarter of the state predate the Revolution by decades.
The second- and third-oldest farms on the list date from 1717 and are in Lancaster County, the richest farming area of Pennsylvania.
Closer to Philadelphia, housing, highways and malls have eaten open space. But the list includes 37 farms in Chester County, 27 in Montgomery County, 22 in Bucks County, and two in Delaware County.
"There are probably others of equivalent age that are not on the list," said Nancy Mohr, of Chester County 20-20 Trust, one of several organizations sponsoring a recognition event for that county's farmers Feb. 10 at Pennsylvania State University's Great Valley campus.
New Jersey also keeps a registry of century-old farms. Its list of 82 farms includes five that are older than any in Pennsylvania. The Brookdale Farm, in Bordentown, Burlington County, owned by Frank Wallace Jr., goes back to 1677.
Like descendants of many early farm families in both Southeastern Pennsylvania and South Jersey, Frank Mendenhall has a Quaker heritage.
The first Mendenhalls arrived with Penn from England in 1682. They settled in what today is Concord Township, Delaware County. One of them later bought a parcel of land with natural spring water in Pennsbury Township, Chester County. That is where the Mendenhalls remained.
From the end of a rutted drive, they have watched the history of the country go by.
In September 1777, British supply wagons rolled past on the morning of the Revolutionary War Battle of Brandywine.
In April 1861, Mendenhall's great-grandfather was putting in fence posts down beyond the railroad tracks when a mail train came through with word that Southerners had fired on Fort Sumter, the act that precipitated the Civil War.
In November 1963, Mendenhall and his father learned from the TV in the living room that President John F. Kennedy had been shot and killed in Dallas.
Mendenhall, who at 64 has never lived off the farm except when he was in the Marines, said he feels a responsibility to guard his legacy.
On a crisp recent morning, with ice in the buckets and horse droppings crunching underfoot like charcoal briquettes, he was asked whether there was any amount of money that could entice him to sell the farm, which now encompasses 88 acres.
Wearing a soft cap, he thought for a moment and replied, "I doubt it."
A former mechanical engineer for DuPont Co., Mendenhall does carpentry to supplement farm income, which mainly comes from growing hay and stabling horses. Dairy operations ceased in 1949.
"It's a working farm, but for me, it's not a full-time occupation," he said.
His wife, Patricia, works at a women's clothing store and runs the farm day to day. The younger of their daughters, Lauren, shares their 10-room, Georgian-style home, built in the 1700s and expanded in 1836. Older daughter Megan and her husband live over the spring house. Seven dogs and two cats have the run of the place.
Mendenhall said he is often asked whether the house has ghosts.
"We always say, well, if we do, they're all relatives."
The parents plan to leave the farm to the daughters. They hope at least one of them will want to preserve it. But they know it should come from the heart, not from a sense of duty.
"I don't want to force them," Frank Mendenhall said. "They have to take the step themselves. If you have to force them, they never will. They'll leave as soon as I go."
In any family, it isn't easy to keep the chain unbroken. Just look at what is happening with the oldest farm on the state registry in Montgomery County.
Situated in Franconia Township, near Souderton, it was founded in 1753. Owner Richard Snyder, 72, recently sold it.
In March, earthmovers will begin turning his 45 acres, on which he had raised black Angus cattle, into 110 units of housing for people age 55-plus.
Snyder and his wife, Phyllis, will stay in a house they built in 1960. But an older house and a barn will be torn down.
Snyder, the eighth generation of his family on the land, makes no apologies. He said he didn't even know that his farm was Montgomery County's oldest on the registry.
"Change is inevitable," he said, "and you go along with it."
His parents were the ones who registered the farm. They lived to be 90 and 93. But they've been gone since 1986, and Snyder is looking at his own late-life plans. He and his wife have no children.
"Since 1986, a few things have changed. I'm not going to last forever. . . . If I were 54, I probably wouldn't be thinking of selling. . . . There are times when you have to make a decision."
The oldest registered farm in Bucks, near Perkasie, dates from 1734.
The oldest in Delaware County, which was heavily developed after World War I, goes back to only 1864.
Even in rural Lancaster County, development pressures - and consequent rising prices - are making it tempting for farm families to sell out.
Harry Zimmerman, who owns one of the farms there dating from 1717, said: "If the farm didn't mean a lot to me, I wouldn't be here anymore.
"I never worked at anything else," he said. "I'm doing something I feel I should be doing - taking care of the ground and tilling the soil."
But he worries that his 19-year-old son, Scott, who works on the farm, won't make enough money from the dairy herd over the long haul to justify the hard labor of agriculture.
Like Mendenhall and many other Pennsylvania farmers, he has reduced his taxes by enrolling in a program that assesses his land according to its agricultural value rather than its development value.
But he hasn't taken the second step of preserving the open space for perpetuity by selling off the development rights.
He doesn't want to short-shrift his two boys if they ever want to sell for full market value. Still, he said, the money would be nice right now.
"I'm 62 and I still can't retire. You're kind of rich-poor. If I wanted to sell everything, the farm would bring a real high price. But I don't want to do that."
Contact staff writer Tom Infield at 610-701-7622 or at email@example.com.
The (Really) Old Homestead
These are the oldest registered farms in each county in the region that have been continually in one family for at least 100 years.
Current Owner Town Established
Earl Landis, George & Ruth Stefler Perkasie 1734
Glenn & Glenda Wismer Perkasie 1749
Benjamin Smith Wycombe 1756
Frank & Patricia Mendenhall Mendenhall 1703
Thomas & Elizabeth Martin West Grove 1727
William & Ruth Handy Coatesville 1743
Jesse Darlington Darling 1864
Alfred Dallet Jr. Cheyney 1875
Harry & Elizabeth Zimmerman East Earl 1717
John & Ruth Miller Lancaster 1717
J. Fred & Frances Shenk New Providence 1720
Richard Snyder Souderton 1753
Sherman Heebner Collegeville 1754
Margaret Souder Telford 1755
Frank Wallace Jr. Bordentown 1677
Joseph H. Taylor Cinnaminson 1720
Anna Black Chesterfield 1730
Christopher Moore Thorofare 1699
David Scott Sewell 1837
W. Kirk Horner Harrisonville 1865
(None in Philadelphia or Camden Counties)
History of Springdale Farm
Highlights of the 300-year history of Springdale Farm in Mendenhall, Chester County, the oldest continually operated family farm in Pennsylvania.
1703 Land purchase from William Penn's agents.
1777 British army supply wagons pass the farm on the morning of the Battle of Brandywine.
1830 Brothers Isaac and Ellwood Mendenhall divide property, and Oakdale Farm is established next to Springdale Farm.
1850 Ellwood Mendenhall is elected the local justice of the peace. This enables him to protect a branch of the Underground Railroad running through the neighboring farm.
1860 Ellwood Mendenhall purchases additional land to establish Mendenhall train station and, later, the town of Mendenhall.
1890 Bethany Presbyterian Church is established in the living room of the main house.
1914 Dairy barn burns to the ground and reconstruction begins.
1949 Dairy operations cease.
1970 Transition to equestrian facility begins.
Dec. 6, 2003 Mendenhall family celebrates 300 years of continuous ownership.