It's marked by a few green signs along Interstate 40 from Raleigh to Durham. The wide divided highway rises and falls gently past pines and spring-fragrant privet shrubs.
Occasionally there is a modern industrial-looking building to be glimpsed along the way.
Casual observers, merely looking for the next Interstate north, may be forgiven for not noticing that they're driving through the largest planned research park in the world.
In the beginning was a paradox. North Carolina had long had a proud tradition of higher education, boasting, among other fine institutions, the oldest state university in the nation. But the state's economy had relatively few places for university graduates.
Through the mid-1950s the state's industrial base was virtually all in the traditionally labor-intensive, low-wage areas of textiles, tobacco, and furnituremaking.
So many educated North Carolinians had no choice but to pursue careers outside their native state. In fact, the 1950 census found fully 20 percent of those born in North Carolina living outside the state. Back on the home front, North Carolina languished at the bottom of the list of states in terms of per capita income and average industrial wages.
During the middle 1950s, though, an idea began to develop: Why not plug the brain drain with a research park?
The three universities in the Raleigh-Durham-Chapel Hill area could serve as its basis. National firms would be drawn into the state, first for research in the park and then for manufacturing outside it.
New ''spinoff'' firms would develop, too, it was thought, as was happening along the Route 128 beltway around Boston. The park would thus help accommodate university graduates in the state's economy, and ensure North Carolina a place in the high technology sun just discernible on the horizon at that time.
The idea hatched in the minds of several people simultaneously, but it is particularly associated with Luther Hodges, the former textile executive who was known as North Carolina's ''business development governor'' (and later as President Kennedy's commerce secretary).
And so the Research Triangle Park (RTP) came into being. Modeled loosely on the Stanford Research Institute, it is run for the three ''triangle universities'' -- University of North Carolina at Chapel Hill, Duke University in Durham, and North Carolina State University at Raleigh -- by a not-for-profit organization, the Research Triangle Foundation.
The park's success in plugging the brain drain is indicated by one statistic citizens wave around like a football pennant: The Raleigh-Durham metropolitan area has more PhD engineers and scientists per 100,000 inhabitants than any other urban area in the United States.
RTP now has some 20,000 employees and an annual payroll of $500,000. It sits on some 5,500 acres of rolling, pine-covered Carolina countryside that was once too poor to farm but today is harvesting a lucrative new crop, ideas.
Dozens of other states and communities are now trying to pattern similar talent-oriented centers after the park, which lies mostly in Durham County but also in Wake County (Raleigh), between the three cities and the three universities.
Yet if researchers here are dreamers and thinkers by trade, they are pragmatists by profession. The park is oriented toward coming up usable widgets, not just theories and ideas (Monsanto's Astroturf, for instance, came out of a lab here).
David Godschalk, a professor in the department of city and regional planning at University of North Carolina-Chapel Hill, calls it ''a beautiful example of a co-produced facility. . . . You had the real movers and shakers in both the public and private sectors doing something that nobody else had ever done.''
The park has some 40 tenants, plus ''support services'' such as banks, travel agencies, a delicatessen, an inn, and a US post office (with its own zip code). The tenants are heavy in high-technology industry: International Business Machines, Data General, Northern Telecom; life sciences and pharmaceuticals (Burroughs Wellcome, Becton Dickinson); and state and federal government research facilities such as the US Environmental Protection Agency, the National Center for Health Statistics, and the North Carolina Science and Technology Research Center.
Operations in the park range in size from IBM's 5,500 employees down to a half-dozen or so in the case of small consulting and research firms.
Ned Huffman, executive vice-president of the Research Triangle Foundation, estimates that some 60 percent of the park's employees are professionals -- with baccalaureate degree or higher -- and the rest technical, support, or clerical workers. Most outfits bring in their own top staff from outside, but a large percentage of the professionals are hired locally, as well as almost all of the support staff.
There are some 2,800 acres still unsold, but even the developed acreage isn't what you'd call built up. Under the protective covenants of the park, only 15 percent of each tract may be built upon, and buildings must be set back 250 feet from the road.
Covenants also restrict the park's tenants almost exclusively to research, although the original rules were stretched somewhat to let IBM and others do ''assembly'' or ''research applications'' work -- which officials hasten to say is not the same thing as ''manufacturing.'' In any case, there are no belching smokestacks on the horizon or freight trains rolling through the middle of the park.
RTP was a long time getting off the ground.
The first tenant, in 1960, was the Chemstrand Research Center, now known as the Monsanto Triangle Park Development Center Inc. Through the early '60s the park struggled along with a few tenants, including the Research Triangle Institute, a contract research organization set up by the Research Triangle universities but under separate board and management. It has had a sort of flagship role, promoting the RTP concept, but its importance has become less critical as the park has taken off.
Takeoff came in 1965, when IBM decided to move into the park. Although IBM officials profess a certain embarrassment at hearing it said, in the triangle as in other parts of the country, IBM's presence in an area is a powerful endorsement.
Another milestone came in 1970, when Burroughs Wellcome, the pharmaceutical firm, moved its corporate headquarters here from New York. Corporate headquarters are otherwise conspicuous for their absence from the park. And nit-pickers could point out that Burroughs Wellcome is actually the North American subsidiary of a British firm.
But, says Mr. Huffman, ''We don't look for corporate headquarters -- that's just an add-on when we do get one. Our thrust is research.''
In any case, the wooing of Burroughs Wellcome is a classic story of what Southerners had to go through to get Northern industry a decade ago. There are jokes about how the New Yorkers had been told not to worry about mosquitoes down South, since the snakes would eat 'em. Park officers flew planeloads of New Yorkers into Raleigh-Durham Airport for weekend visits, and shipped triangle residents to New York for social exchange.
It's all become easier as Sunbelt industrialization has gained momentum and RTP has become better known.
The trickle of new firms into the park continues. Three companies are said to be looking into putting operations there. Despite the recession, the fewer than 500 jobs lost in the past year are outnumbered by new jobs created in the park.
Ned Huffman is both ''proud and irritated'' that so many people come to visit the park -- to learn how to reproduce it at home. He waves several pages of a yellow memo pad listing visits over the past year by delegations from universities and cities all across the country, frost belt and Sunbelt, as well as from overseas, notably Japan and Korea.
''But there's a very limited market for what we're doing. There are only some three or four new research centers built per year across the country,'' he says. Many of these turn into de facto industrial parks, rather than research parks, and some even fold.
He contemplates the list of universities and eager-eyed chambers of commerce that will probably be disappointed in 1982 and sighs. In a certain way, Mr. Huffman observes, RTP's success story isn't quite part of the Sunbelt boom; you might say it is in the Sunbelt but not of the Sunbelt.
North Carolina has several things going for it to make it a textbook example of Sunbelt industrialization. But Mr. Huffman says he feels the park could have succeeded just about anywhere -- except Antarctica, maybe -- that had the right chemistry of the three universities, plus the quasi-official backing of state leaders.
One part of the RTP scenario that hasn't been played out yet is the founding of new firms. Mr. Huffman attributes this to lack of venture capital in the area but expects the ''spinoff effect'' will begin fairly soon.
But Dr. Craig Casey, head of the electrical engineering program at Duke, sees it otherwise: ''I've had people come to my office and say, 'If you've got people who have good ideas, bring them to us.' '' But the research just hasn't matured to the right point yet, he says. ''As you sample the spawning bed, it's just not fertile enough yet.''