BISMARCK, N.D. — Forget South Dakota. North Dakota’s most similar sister state these days is some 2,000 miles away.

Alaska and North Dakota — which once had little more in common than wintry weather and elbow room — have for the past several years been locked in a state sibling rivalry over population numbers and crude oil output.

“It shocks me how much we have in common with Alaska, and it’s not just the cold,” said Kevin Iverson, manager of the census office at the North Dakota Commerce Department in Bismarck.

North Dakota is bettering Alaska on crude production and the number of residents now, thanks to the Lower 48 state’s economic miracle led by its oil bonanza. The United States’ unlikely economic darling that is North Dakota comes in contrast to slipping crude production on The Last Frontier.

Recent U.S. Census Bureau data show North Dakota recaptured the 47th most populous state from Alaska, which had held the ranking for the past decade. North Dakota had an estimated 739,482 residents in 2014, up more 15,600 residents from the prior count and a record level. The 2.2 percent increase was the biggest in the nation.

Alaska lost more than 500 residents between 2013 and 2014, ending the year with a population pegged at about 736,700. It was among only six states to lose population, data show.

North Dakota’s fortunes have swung radically in recent years with advanced drilling technology in the rich Bakken shale and Three Forks formations that have thrust the state to the nation’s No. 2 oil producer behind Texas. North Dakota, which was barely a top-10 oil producer a decade ago, passed Alaska in 2012 to become the second-leading oil-producing state in the U.S.

Oil output in North Dakota is pegged at more than 1.1 million barrels daily, or more than double Alaska’s oil production, which peaked in 1988 at 2 million barrels daily but has dropped to less than one-fourth of that at present.

Two of North Dakota’s 17 oil-producing counties in the western part of the state — McKenzie and Mountrail — are now producing more than all of Alaska.

North Dakota’s present day position seemed inconceivable in 2003 when it was the only state to lose population and Alaska vaulted past. Only Vermont and Wyoming had fewer residents than North Dakota then, and both of those states had population increases, the Census Bureau said.

Demographers projected at that time that Vermont and Wyoming would leapfrog over North Dakota by decade’s end, leaving North Dakota with the dubious distinction of being the least-populated state in the nation.

The Census Bureau later estimated that about 21,000 North Dakotans left between 2000 and 2007, the year the state’s oil boom began in earnest. North Dakota has since added nearly 84,000 residents and has about 25,000 more jobs than takers, giving it the lowest unemployment rate in the nation, less than 3 percent.

Iverson, North Dakota’s demographer, said the explosion of oil development has made population estimates difficult, if not impossible.

“There is a real danger of doing population projections based on oil,” he said. “The problem for small rural states like North Dakota and Alaska is that population is driven by migration change and that change is driven by economics.”

Alaska demographer David Howell, based in Juneau, said most residents there are aware of North Dakota’s newfound oil wealth.

“We know what’s going on with oil in North Dakota and it’s something people here are always keeping track of,” he said. “People are talking about the boom down there.”

The recent population estimates, however, do not paint a gloom-and-doom picture for Alaska, Howell said. The state’s overall economy remains strong, he said.

“Certainly the statewide (population) estimates show a slight decrease, but it is not a huge drop by any means,” Howell said.

Bismarck statehouse correspondent James MacPherson is a former longtime Alaska resident.