HOLDERNESS, N.H. — Six mornings a week, Elizabeth Hamilton rolls as much as 100 pounds of ice up a hill in an antique wheelbarrow. The short, steep incline is the hardest stretch of the 20-year-old’s route as a staff member at the Rockywold-Deephaven Camps, two family camps founded in 1897 that still preserve antique traditions.

Among the camp’s curious throwbacks are the antique iceboxes that stand in each cabin at the site around Squam Lake. The metal and wooden relics require a top-up every morning with blocks of ice that keep the interior cold even on the hottest summer days.

“It’s tradition,’’ Hamilton said, wiping her hands on her staff shirt after finishing a delivery. “My family’s been coming here forever, and it’s always the same.’’

Reminders of a bygone era, the iceboxes are now a cool way to keep cool, part of the camp that guests love.

“I still refer to refrigerators as iceboxes, and people look at me strangely,’’ said David Wyeth, 64, a longtime guest. “This is the only place where I can really say, ‘I have an icebox,’ and I am accurate.’’

Ice harvesting has been part of the package at RDC since the camps’ founding. Back then, iceboxes were almost a luxury for late 19th-century vacationers and guests in an era of straw boater hats and travel trunks. When the camp installed electric refrigerators in the 1960s, families balked. The iceboxes came back, and stand today as part of the camp’s brand, an allure of rustic memories.

“It changes, but we try not to make it feel like it changes,’’ said John Jurczynski, referring to RDC, which he has comanaged for 29 seasons. “It’s like going back in time.’’

The all-inclusive camps offer period cabins, three daily meals in a communal dining hall, and activities such as canoeing and hiking, with boats and games. A weeklong stay in a small cabin for a family of four could cost around $4,000, he said.

Every January, RDC has an ice harvest to stock up for the summer, an event that still occurs in several towns around New England. RDC is rare for preserving the ice for regular use, and has one of the only active public icehouses in New England. Many of the other harvests use the ice only for an old-fashioned ice cream social once in the summer.

Once the ice is harvested at RDC, it is moved into an icehouse on site. There, the microwave-sized blocks sit in the 3-foot deep foundation under layers of insulating sawdust, packed tightly together.

During the summer, Hamilton and other staffers climb into the building, use antique ice tongs to extract individual blocks, and hose them down to clean off the sawdust.

Then, they load the blocks into four identical wheelbarrows and deliver them to the iceboxes, each of which has two sections: one for the ice, and one for beverages and food.

“It’s simple living,’’ Jurczynski said. “Even back then, a lot of the folks who came here were from cities, and this was a way for them to engage with the environment, spend quality time with their families.’’

The ice industry started in 1806 when Massachusetts native Frederic Tudor began selling the frozen commodity from his father’s lake in Essex to the Caribbean. In a few years, Boston’s “Ice King’’ had started shipping ice all over the world, chunks of New England lakes finding their way to England, India, and even Australia.

While watching the ice cutters on Walden Pond in the 1840s, Henry David Thoreau wrote: “The pure Walden water is mingled with the sacred water of the Ganges.’’ The trade was popular throughout the 1800s, after the railroad started to move it around, but before electricity became a household staple.

At RDC, the history of the place is as much part of the ice harvesting as the broader regional history. Families relish the continuity of the summers.

“The icebox is just life to me, because I grew up with one,’’ said Marian “Tockie’’ Baker, 91, who has been coming to the camp since 1941.

Her parents started coming in 1911, she said. Baker met her future husband in the communal dining hall when she was 17 and he was 18, right before he signed up to fight in World War II. They came almost every year since and, after his death, she still hikes the familiar trails with her adult children.

“It feels like a second home up here, if not a first,’’ she said.

The family of Hamilton, the camp staffer, also has deep roots here. They have been coming since 1904, and her grandparents met at RDC when they were children. They brought their children and grandchildren to RDC for regular family vacations.

“The joy was just that we were all around in the same place,’’ Hamilton said. “Grandma just loved that we were getting to know each other.’’

Both her grandparents died recently. She thinks about them every morning when she delivers ice to the small two-person cabin they used to share, with a large screened-in porch and two rocking chairs where they used to sit and overlook Squam Lake.

Next summer, she and her family plan to return here to remember the two and to say goodbye.

“This is where their ashes will go,’’ Hamilton said after sitting on the dock in silence, gazing out at the water. “This is the place.’’

Amelia Nierenberg can be reached at amelia.nierenberg@globe.com.