More than half a century after Penrose Hallowell started a dairy on 70 picture-perfect acres in upper Bucks County, Pennywell Farm is still operating. So are dozens of other farms that, while downsized over time, have traditionally ruled these rural environs.

That is the miracle of Tinicum Township, a 30-square-mile bailiwick where little changes, even as development gnaws at the edges.

Through notoriously stringent ordinances and dogged land-preservation efforts, Tinicum has kept an iron grip on its agricultural ambience, its rolling fields, scenic hills, and lush valleys. And it won't easily let go, even after two courts have ruled it must give way to builders' bulldozers.

The next stop could be the Pennsylvania Supreme Court, which has yet to say if it will hear the case.

Tinicum has "effectively made it difficult for anyone to even build a house," the 83-year-old Hallowell, a former Pennsylvania agriculture secretary, said. "If you want to keep people out, and not change Tinicum, it's good. If you think that's not fair to young people or the general population, it's not good."

Those perspectives clashed head-on when developers proposed five projects that would add more than 500 apartments, condos, and houses to a township of fewer than 4,000 residents. In much of Tinicum, lots must be a minimum two acres, so the builders set their sights on the niches designated for denser development. But even there, if the township finds rich agricultural soil, an ordinance limits development to 25 percent of a tract.

Main Street Development Group Inc., of Warrington, sued the Tinicum Board of Supervisors and got a favorable ruling from a Bucks County judge, who found the ordinance unfairly restrictive. In March, Commonwealth Court upheld the decision.

The supervisors, joined by a group of residents, have asked the state Supreme Court to take their appeal.

"There's an awful lot of people who think all we're talking about is closing the gate, and no one else is welcome. It's simply not the case," said Boyce Budd, a farm owner who is chairman of the supervisors. "What I think most people object to are these great big housing developments out in cornfields, away from any kind of town.. . .

"That to me is a sin against nature and mankind."

The so-far-victorious developers see only unlawful impediments to the inevitable.

"Bucks County has exploded, and every [other] municipality has lost farmland," said Robert Gundlach, attorney for the developers. Tinicum supervisors are "so uncooperative."

Unless the Pennsylvania Supreme Court intervenes, the stage could finally be set for the kind of development that Tinicum has watched encroach on its neighbors - notably Buckingham and Plumstead Townships to the south, where farm after farm has disappeared.

The developments would spring up mostly near Route 611, with 400 of the homes occupying what once was a large Christmas-tree farm. One project is planned for a parcel that Budd called "the most beautiful portal to Tinicum that I have yet come across."

Of the township's 19,000 acres, nearly 7,000 - more than one-third - are preserved in perpetuity, either through the nonprofit Tinicum Conservancy or county agricultural easements. "We're all concerned about what's going on," said James Engel, the conservancy's executive director. "The scale of that development would be something that Tinicum hasn't experienced."

The township does not eschew all development. Its two-acre rule is tailor-made for farming - or modern mansions, which Gundlach said make up the bulk of recent building in Tinicum.

Hallowell, who headed the state agriculture department in the early 1980s, noted that townships are obliged by law to accommodate many kinds of land use.

While its agricultural aura may be intact, "Tinicum is not farms now. It's estates," said Hallowell. The supervisors approve multimillion-dollar homes, "but they don't want to approve anything for $225,000."

Even in areas that the township zoned for commercial or multifamily use, development is stymied by the presence of high-quality soil.

That devalues property, said developer Rob Sigety, president of the Piper Group, which wants to build homes in Tinicum. Of the supervisors, he added, "I just think they've gone a little too far."

Two courts agreed. So, while funding major legal challenges is not easy for strapped townships, Tinicum is plowing ahead. Budd, the board chairman, said he was buoyed by a recent state Supreme Court ruling that spared neighboring Bedminster Township from some development.

On a recent Friday evening at the Ottsville Farmers Market, just up the road from Hallowell's spread, farmers did a brisk trade in produce.

There was a line for Mexican fare at famed chef Jose Garces' Guapos Tacos truck. Garces, who has appeared on the Food Network's Iron Chef America, bought a 40-acre farm in Tinicum to supply his restaurants.

Boutique farms are the rage now, specializing in organics or single crops.

"Everybody wants to move to Tinicum because they've done so much hard work in preserving this land," said Margaret Balitsaris, owner of Come-Along Farm. She worries about the "domino effect" of one development after another suddenly rising, she said. "It would be awful."

Logan Bonner, of Revere, was busy selling an assortment of wild mushrooms, many of which he found while foraging the open spaces nearby.

"I don't know how much more stress the system can take," he said, "before we destroy this area."

Hallowell knows, though, that even in Tinicum it's tough to stick it out as a farmer these days, between trying to get decent prices on crops and navigating regulations. He has put Pennywell, now run by his son, into protective custody forever, so it will never be developed.

"The best crop on the farm has been our children, grandchildren, and now our great-grandchildren," he said. "That's been a good harvest."

Contact staff writer Emilie Lounsberry at elounsberry@phillynews.com.