This mom didn’t just hike all 48 of N.H.’s 4,000-foot peaks. She did it along with her three young kids.

The Pearsons have taken the phrase “Start ‘em young” to another level in New Hampshire’s White Mountains.

With her daughters, Lydia, 6; Demi, 3; and Moriah, 1, in tow, Webster, N.H., resident Whitney Pearson recently completed a thru-hike of the state’s 48 peaks above 4,000 feet. She carried her youngest along with 60-plus pounds of food and gear throughout a five-week adventure while her older daughters navigated 230 miles and nearly 80,000 feet of elevation gain on their own two feet.

Two years prior, when she was 4, Lydia became the youngest to climb all 48 mountains, doing so in the more traditional fashion, with day hikes and a couple overnight trips broken up by long stretches at home. This time, she and her sisters hiked through, one peak after the other. Demi now holds the title as the youngest to finish the 48.

“I wanted them to experience a true thru-hike as closely as I could,” said Pearson, who grew up in the North Conway area and played softball at Plymouth State. “We knew we weren’t going to go home, and that was a struggle at first, but once we got into a groove, they were loving it.”

Known as the Direttissima (Italian for “the most direct route”), a thru-hike of New Hampshire’s 4,000-footers requires hikers to connect the 48 summits in self-powered fashion. There is no driving between trailheads, but hikers can leave the route at road crossings to replenish and resupply before picking up where they left off.

Following years of planning and warm-up treks with the kids, Pearson stuffed her Ford Bronco full of gear and groceries and drove to the Beaver Brook Trailhead under Mount Moosilauke in Woodstock to start on June 18. They followed the most heavily traveled route on trails through the Pemigewasset and Sandwich Wilderness areas, north over Mount Carrigain and through Crawford Notch, then over the Presidential Range and neighboring mountains toward the finish at Mount Cabot.

Friends or family members moved her car between trailheads or assisted in shuttling the vehicle, and a few put the Pearsons up for a night in a real bed. Her husband, Eric, met them at several crossings. Seeing their dad or the Bronco rustled up emotions, but Pearson said the girls never asked to call off the trip.

In total, the Pearsons spent five nights with family, four in hotels, five in Appalachian Mountain Club huts, five at AMC campsites, and 15 camping in the backcountry. Lydia and Demi enjoyed those nights by a fire more than anything.

“I had no idea how this was going to go. I had no expectations,” said Pearson, an accomplished ultrarunner with several speed records on long-distance routes in New England. “Whenever [the girls] said, ‘We’re done,’ then we were done. But they just love being outside. They talked about this hike for so long; they never asked to stop.”

Trails in the White Mountains are notoriously rugged. Yet Demi and Lydia often told their mom, “I got it,” before problem-solving their way up a rocky section or splashing through a stream. Of course, Pearson kept a close watch and offered a helping hand despite dealing with a massive backpack that ballooned with food and water after each road crossing.

The hardest part for mom? Parenting.

Without the threat of losing screen privileges, or bedrooms to send the girls for a timeout, she had no real recourse for their behavior. Whether Demi and Lydia were fighting and complaining, or marching on cheerfully, the daily itinerary couldn’t change much.

“I’m impressed by it all, but I think I’m most impressed with Whitney’s mental capacity to even desire to do something like that with her kids,” said Sarita Ojala, who often brings her children on hikes with the Pearsons, and joined them at the start and conclusion of their thru-hike. “It takes a lot of patience to hike with kids and keep them motivated. And when you’re home you can let your kids roam without worrying, but you can’t do that as easily on the trail.”

Just two days after completing their journey on July 23, the Pearson girls were asking about the next adventure, and a week later, they were hiking Mount Monadnock with the Ojalas.

While she hopes to take them on a thru-hike of Vermont’s five 4,000-footers next summer, and is quite proud of their passion for the mountains, Pearson and her husband encourage their daughter’s varied interests.

“I do like them to experience hard things, but I don’t want people to think I’m trying to turn them into ultrarunners,” said Pearson. “I’m just trying to teach them about not quitting when they’re pursuing their goals.”

“They have confidence in anything they do and I would have to attribute some of that to hiking.”