It was with a touch of truant glee that Kopseng skipped out of his office to fly me around the oil fields on a windy morning last spring. He pulled on a green Fighting Sioux sweatshirt and climbed into the cockpit of his Aviat Husky, a maroon-and-yellow single-engine plane with two seats, one behind the other.

And then we were off, banking over the low-slung rooftops that ring the state’s Capitol, an 18-story stone-and-concrete landmark built in 1934. North Dakotans are as proud of their Capitol as they are of their boom-based unemployment rate (3.2 percent, lowest in the nation), and many were stung when a Minnesota state legislator last spring compared it to the headquarters of an insurance company.

We crossed the Missouri River, the plane beating on above a sea of grass. Infinity nagged at the scale of things. It was almost possible to imagine the land as it appeared to Lewis and Clark when the Corps of Discovery came up the Missouri in 1804 — but only if you looked past the toy-size trucks crawling west on Interstate 94 with drill pipe and water tanks; and the locomotives lumbering east with hundred-unit trains of black oil-tanker cars in tow. The westward march of American industry was written in the quarters of plowed earth and section line roads, in the power-transmission towers and smoke-signal steam puffs drifting from a Tesoro refinery; it was visible even on the far horizon, at the edge of a fretted but still bracing emptiness, in the shape of giant windmills and the silhouette of a coal gasification plant. Each and all were contemporary manifestations of an economic imperative that dates back to the triumph of the treaty breakers who usurped the Native Americans and commodified the land, and to the waves that came in their wake, the great white hunters who cleaned out the buffalo, the agents of the bone boom that followed who sent trainloads of buffalo skeletons back East to be used to refine sugar, the iron-horse magnates, the immigrant farmers and pioneer ranchers ruined by the “dirty ’30s,” and later the first oil and lignite coal barons and the government dam builders who tamed the Missouri.

“Keep an eye out for radio towers,” Kopseng said over the headset.

Flying was Kopseng’s dream job before he got the idea of building an oil company. He began studying for his pilot’s license as a freshman in college. When he graduated (sidetracked for a year and a half by a stint in the Army that included seven months in Vietnam), one of his first jobs was flying a small plane for a highway contractor. He always worked — he helped his parents run apartment buildings in Bismarck, and for six summers starting at age 12, he fed the chickens and pigs and bucked hay and branded cattle at his grandparents’ ranch in Slope County in the western part of the state.

Kopseng first came down with oil fever in the late 1970s, when fortunes were being made domestically in the wake of the OPEC oil embargo. He struggled for five years, learning expensive lessons. “I had a lot of lemonade wells,” he sighed. He went broke twice, maxed out his credit cards and even borrowed money from his mother — loans that came with sharp remarks about his clothes and hair. After he married and started a family, it was his wife’s friends who looked at him sideways. While they were buying houses and investing in mutual funds, he was in debt-work-out negotiations with Halliburton.

“I embarrassed myself,” he said.

In 1984, at a particularly low ebb, he met Don Russell, a merchant from Mandan, who’d done well in the not-obviously-related businesses of peddling tires and packing meat. Russell, who died in 2011, also wanted to get into oil and gas. The timing might not have seemed auspicious; companies were quitting the Williston Basin, unable to sell their product for more than it cost to produce. But with Russell handling the financial end, Kopseng began accumulating distressed oil and gas wells. He brokered oil-field equipment; he bought and sold leases; he jumped into the natural-gas market just as it was being deregulated. In 1997 he and Russell consolidated various energy-related businesses into the privately held United Energy Corporation.

U.E.C. hasn’t drilled a well of its own since 1998, but today it holds a nonoperating interest in close to 2,000 oil and gas wells. It transports by rail 82,000 barrels of oil a day to refineries. In 2012 the company earned a net profit of $44.8 million on revenues of $5.7 billion. Best of all, in a state where until recently young people often had to leave to find work, his two sons — Ryan, an oilman, and Sander, a lawyer — joined the company and built successful careers down the hall.