FREEDOM, Wyo. — Two weeks before the first day of school in Star Valley, summer feels like it could last forever. But in a place where the rivers begin as snow, the season of swimming is short. Even in August, the creeks run cold. Too soon, they will freeze.

Six-year-old Soren Johnson stands on a pebbled beach where Jackknife Creek pours into the Salt River. This creek, this river, and two dirt roads mark the boundaries of his kingdom: Jackknife Creek Ranch, 20 acres of pasture, willows, and aspen groves once part of a working dairy farm. The ranch kisses the western edge of Wyoming. Across the street is Idaho.

Jackknife Creek begins around 20 miles west, on Idaho’s Caribou Mountain, and meanders into Wyoming’s Star Valley, a mile-high rural basin roughly an hour’s drive south of Jackson. Soren and his brothers, 8-year-old Killian and 16-year-old Hatton, have no access to a swimming pool. They have a creek blessed with oxbows, beavers, wild trout, and swimming holes sacred to free-range kids. It thaws in late spring and swells until May, too fast and high and filled with sticks to be safe for swimming before late June or July.

The only thing keeping Soren out of this creek is a puncture wound below his left knee. He fell on a rusty nail while playing in a 101-year-old barn. It wasn’t bad enough for a 40-minute drive to the hospital, but the skin is a little red and hot. He’s been limping around theatrically and insisted on a piggyback ride to the creek.

But now, squishing around in wet sneakers, Soren jealously eyes brother Killian, who is up to his chin in the creek. The air is 81 degrees, but Killian’s teeth are chattering. Soren’s eyes grow wild with longing and he bounces from foot to foot, his gimpy leg now pain free.

“Mom, can I please try swimming?” he says. “Look, I can walk normal now!”

Freedom, Wyoming has a post office, a church, zero stoplights, and a postcard-perfect fly fishing river with Snake River cutthroat trout. It is home to cattle ranches, dairy farms, and Freedom Arms, maker of one of the largest-caliber handguns on the market, used for hunting trophy game, even bigger than the .44 Magnum Smith & Wesson, the gun Clint Eastwood used to make his day.

Jeremiah and Lindsey Johnson, the boys’ parents, were living in Jackson when they fell in love with this land and the life it promised. Jeremiah builds high-end homes in Wyoming’s wealthiest ZIP code. Lindsey, a former interior designer, bakes cakes for luxury weddings. They wanted to raise “wild Wyoming boys” in a place with creeks to explore, snakes to catch, and meadows to roam in the company of chickens, goats, and horses.

The boys feed kitchen scraps to the hens and gather warm eggs with yolks so bright they can make a white cake blush. After chores, they scatter to catch tadpoles, poke at bugs with sticks, and hide in the willows that shade the creek. They’re chaperoned by a rescued yellow lab named Jackson. Even Jackson knows the dinner bell means it’s time to run home for supper. “They play so far away I got tired of yelling,” Lindsey says.

They play at least five sports with a soccer ball: baseball, volleyball, golf, soccer, and Keep It Off the Ground. Sometimes a foul ball gets stuck in an Aspen tree. They have a skateboard — but no pavement — so they ride it down a grassy slope, a summertime version of sledding. There’s a bike to pedal through freshly mowed fields, but the front wheel is missing an axle. That doesn’t stop them. But Dad does. They didn’t watch the Olympics. “I don’t even know what that is,” Killian says.

Summer days promise 15 hours of daylight. But the season is fleeting. Snow comes in October, and by November it’s starting to pile up higher than a boy is tall. It doesn’t melt off until May. When the snowless season is less than five months, you learn to play hard and soak up summer like a camel stores water. Punishment is having to stay inside.

In two short weeks, a bus will collect the younger boys from their driveway on State Line Road and haul them off to first and third grade. School isn’t bad. Last year, Killian’s school had a five-star view of the Tetons and a warning bell that rang when herds of wild bison wandered too near. Mom took them school shopping in Idaho Falls, nearly two hours away. The mall was an adventure.

“They think Idaho Falls is downtown Manhattan,” Jeremiah says.

“You should see them on an escalator,” Lindsey adds. “It’s like the movie ‘Elf.’”

The sun is sinking through gauzy curtains of light, a cherry orb that glows in the smoky haze from fires burning to the west. Each sunset comes a minute or two sooner than the last. Summer is slipping away. Jackknife Creek, with all its glory and bacteria, beckons irresistibly.

“Please, mom?” Soren pleads. “Please?”

His mother smiles.

Now he’s up to his curls in the creek.

Kim Cross is a writer in Boise, Idaho. Her most recent book is “The Stahl House: Case Study House #22 — The Making of a Modernist Icon.”