Utah’s San Juan County — dominated by the Navajo reservation — languishes with one of every four residents (25.9 percent) living in poverty. That is 22nd worst among counties in the West.

At the other end of the spectrum, poverty is rare in Utah’s Morgan County. Just one of every 25 residents there is impoverished — the 11th lowest rate among all the nation’s counties, and third lowest in the West.

These starkly different economic realities emerge from new Census Bureau estimates for 2017 that cover all 3,141 counties in the nation.

The estimates include wage data that mirror another federal study released last month showing Utah’s Summit County has the nation’s 12th highest per capita income. The new data also put Summit’s median household income at 12th highest, $100,879. Morgan County was not far behind at $96,201.

The Utah median household income is $62,518.

Thanks to Utah’s relatively robust economy, six of its counties are among the West’s top 15 for low poverty rates: Morgan, 4.1 percent; Summit, 4.6; Wasatch, 5.2; Davis, 5.4; Daggett, 6.7; and Tooele, 6.8.

The statewide poverty rate was 9.7 percent, compared with 13.4 percent nationally. The poverty threshold for a family of four in 2017 was a household income of less than $25,094.

Morgan County Council Chairman Ned Mecham sees many reasons for his county’s low poverty and high median income.

“A lot of homes are being built here now that are higher-end,” he says — and they attract people with higher incomes, many of them moving out of the Wasatch Front for more room. But they still may commute easily to Salt Lake City or Ogden. “We have a lot of blue sky and clean air.”

In the town of Mountain Green in Morgan County, Mecham says, the cost of building lots now averages about $200,000. “It’s hard to buy a lot for $200,000, and then build affordable housing on top of that.”

He says that has led to some interesting dynamics between wealthy new move-ins and longtime farmers and ranchers. He says the new move-ins come for the wide-open spaces “but complain about people bailing hay at night, or that someone hauling manure got some on their BMW.”

Mecham adds that the county’s dependence on agriculture may also result in low poverty. Many farmers and ranchers are from families “that have been here since statehood, and own their land” — which is increasingly valuable.

Juliette Tennert, director of economics and public policy research at the University of Utah’s Kem C. Gardner Policy Institute, says similar dynamics are driving low poverty rates and high income in Summit, Wasatch and Tooele counties.

“They have proximity to the urban core, where land is constrained,” she says, so they attract wealthier people who want more land and high-end housing, but still live close to the Wasatch Front.

Park City Mayor Andy Beerman said last month — after another study reported Summit County has among the highest incomes in the nation — “We’re ending up with the super-rich, and then the worker class,” a group he defines as hourly wage earners, young people out of college and others laboring in hotels, restaurants and ski resorts.

The challenge, he said, is “what we’re losing is that whole broad middle class — teachers and cops and small-business owners.”

While wealthier people are heading for counties that ring the Wasatch Front, lower-income people cannot afford to do so.

So the poverty rates are higher in most Wasatch Front counties, where lower-income people can more easily afford to live. For example, it is 10.8 percent in Weber County, 10.5 percent in Utah County and 9.2 percent in Salt Lake County.

San Juan County Commissioner Rebecca Benally, who is Navajo, says unemployment and lack of economic opportunity on the tribe’s reservation are main reasons for poverty there.

She says that outside of the reservation, unemployment in the county is about 6 percent. “But on the reservation side, it is about 50 percent.”

She says tribal rules create a difficult, long process to locate businesses on the reservation — and hopes the tribe will streamline that. Benally says tribal programs to help with poverty also aim resources primarily at Arizona and New Mexico portions of the reservation, “because fewer Navajos live here” in Utah and San Juan County.

Other Utah counties with the highest poverty rates include: Piute, 16.7 percent; Iron, 15.6; Carbon, 15.3; and Cache, 13.5.