First in a series of stories celebrating the 100th anniversary of the National Park Service.

MOUNT RAINIER, Wash. — Ten of us, all women, stood beside a small glacier under the shadow of Mount Rainier and smeared thick, frosting-like mud onto our faces until only our eyes and mouths remained visible.

“This is better than a hundred-dollar day at the spa,’’ said Pat Stiles, one of my hiking partners, as she put the finishing touches on her mud facial.

“Plus there’s no place that would have a view like this,’’ added Rachel Vasak, another fellow hiker.

We stood at the edge of a red lake created by runoff from the glacier and looked out across a vast alpine moonscape. Ice patches and snowfields nestled among the rocky rubble, and Mount Rainier’s snow-covered summit rose up from behind a jagged ridge.

We could have used a good spa day at that point, 38 miles into the wilderness from where our cars and clean clothes sat, and halfway through an epic 10-day hike around Rainier. And yet very little could have wooed us off the trail that day. Over the next 13 miles, we would hike through meadows bursting with mountain heather, across columns of volcanic rock, over a rock-strewn alpine pass called Panhandle Gap, and along a ridge where, from one overlook, we counted 18 different waterfalls draining off Rainier’s eastern glaciers and plunging thousands of feet to the river below.

“It’s just ‘brutiful,’ ’’ said Heather Radke at one of our rest stops, an apt description of the day’s route since it included 2,700 feet of elevation gain and 5,500 feet of knee-pounding descent as it passed through some of the area’s most amazing scenery.

Our group of women, all friends through our kids’ school, banded together last summer to tackle the Wonderland Trail, a 101-year-old footpath that circumnavigates Mount Rainier. The trail gains more than 27,000 vertical feet en route, and offers up-close and ever-changing views of the most glaciated peak in the Lower 48 — Rainier has more than 25 named glaciers.

Several women in the group had never been away from family for an extended time, and others had never done a multiday backpacking trip. We ranged in age from 34 to 53, yet the one thing we all shared was a desire to hike through a stunning wilderness area that was just three hours from where we lived, but that many of us had never explored.

Most guidebooks and park literature claim the trail spans 93 or 94 miles, but our GPS devices put the distance closer to 106 miles.

“I’m not surprised it’s longer,’’ said Sarah Pigeon, originally from Merrimac, Mass., who has worked as a wilderness ranger at Rainier for nine years. “Every year we have reroutes on the trails and we don’t necessarily record the mileage changes.’’

The Wonderland Trail leads hikers through temperate rainforest, across fields of wildflowers, along ridges with clear views of massive glaciers, and into alpine zones where marmots sun themselves on rocks and the high-pitched whistle of pikas can often be heard. It also crosses two suspension bridges, offers a peek into a box canyon, and passes by 300-foot-tall trees that have stood their ground for more than 1,000 years. For much of the route, hikers get clear views of majestic Mount Rainier, rising 14,411 feet above sea level. It’s hard to believe this protected wilderness lies just 55 miles from Seattle, a city about the size of Boston.

Mount Rainier National Park became the country’s fifth national park when it was established on March 2, 1899 (after Yellowstone, Yosemite, Sequoia, and General Grant — now part of Kings Canyon). James Longmire, a local mountaineer and entrepreneur, discovered the area’s mineral springs in the late 1800s and built a lodge here in an effort to attract visitors. The park has since drawn everyone from casual tourists to hardcore climbers who come to summit its main attraction: the towering snow-covered volcano, known as Tacoma or Tahoma by local Native Americans.

Rainier, which last erupted in 1894, has two 1,000-foot-wide volcanic craters at its summit and nearly 2 miles of passageways beneath these craters, creating one of the world’s largest glacier cave networks. The majority of visitors, however, stick to lower elevations where there are more than 260 miles of hiking trails and nature paths.

Park rangers and volunteers from The Mountaineers, a nonprofit conservation and recreation group, completed the Wonderland Trail in 1915, giving rangers access to remote areas of the park to help prevent fires and patrol the land. The trail now attracts hundreds of backpackers who typically complete the 106-mile hike in eight to 12 days, staying at backcountry campsites along the way.

We opted for 10 days, so we had time to dip in waterfalls along the way, pull off our boots and enjoy lazy lunches, and chat with other hikers en route, but not so long that our families — including all 17 kids — would need too much therapy. We generally hiked between 9 and 13 miles a day, with a couple of longer and shorter days mixed in.

To get a permit for the backcountry campsites, whether you’re staying for a few nights or hiking the entire route, you need to submit an application between March 15 and 31. Rangers start processing permit requests, in random order, on April 1. Last year, the park received 2,600 applications for about 300 slots. The good news: It offers walk-up permits daily on a first-come, first-served basis, so you still have a shot of getting on the Wonderland Trail if your dates are flexible. (Alternatively, you can go on an organized tour led by the Sierra Club July 3-9 this year.)

Once we had our permit, we bought 10 five-gallon buckets and filled them with homemade, pre-prepared, dehydrated meals, fresh fruit, new socks, and perhaps a flask or two filled with “medicinal’’ beverages, and then delivered these to two ranger stations the day before we began hiking. That way, we could resupply every three or four days along the trail, and not have to shoulder the weight for the entire trip (our packs already weighed between 36 and 44 pounds with just three days’ worth of food).

We started our hike at the trailhead beside Mowich Lake on the northwestern side of the park, which is accessed via a bumpy, unpaved road that dead-ends by the lake. We chose to hike an alternative route through Spray Park — the only time we veered from the Wonderland Trail — because we had heard this route was more spectacular (you can’t go wrong either way). The trail took us through tall forests of Douglas fir and red cedar, by fields of purple gentians and scarlet paintbrush, and across a scree field that demanded sure footing.

We took side trips to see a misty waterfall and to get closer views of an emerald-green lake and the imposing ridges, glaciers, and headwall on Rainier’s northwestern flank. Clouds often engulf the summit, but when “the mountain is out,’’ as locals say, it’s a magical sight — and we lucked out by having mostly clear skies for nine out of 10 days. That wasn’t the only surprise.

“Bear,’’ said my friend Sara Burns, in a hushed but firm voice as we approached a field.

“Sure,’’ I said, and continued marching along.

“No, really, bear!’’ she insisted, clicking her poles together to create noise.

I rounded a bend in the trail and saw a big black bear just 20 feet away, its head buried in a bush.

“Bear!’’ I said to those coming up behind me, and then we all slowly and carefully tiptoed down the path, thankful that the bear was more interested in wild huckleberries than us. We would see another half a dozen bears in the bush or scurrying across fields during our trip. None of them bothered us, but we made sure to hang our food and all scented items (including a boot with peanut butter on it) on bear poles at night, which protected everything from creatures large and small.

The next day, we crossed a suspension bridge over a milky river and hiked up along the sprawling, dirt-covered Carbon Glacier — the lowest glacier in elevation in the Lower 48 (it reaches its terminus at 3,600 feet) — where we spotted several rock slides. We stopped at a creek for lunch and then disappeared into a cool forest where pine needles and moss blanketed the forest floor.

Over the next few days, as we made our way clockwise around Rainier, we hiked by the massive Winthrop and Emmons glaciers, camped near Mystic Lake, which had a tropical jade coloring, passed a herd of at least 40 mountain goats, and spent a night near Sunrise where we had clear views of the sky for spotting the Perseid meteor shower.

Soon enough, our days fell into a natural rhythm, and our biggest concerns became finding clean water, tending blisters, drying clothes, and getting to the next site while enjoying the sights, sounds, and smells along the route. Almost daily, we cooled off under waterfalls, in alpine lakes, or in chilly streams along our path — nature’s ice packs.

One day, we met Ben and Cami Crawford from northern Kentucky, who were hiking the trail for the fifth time, with their five kids, ages 4, 8, 10, 12, and 15.

“Everyone is helping carry something,’’ said Ben, when we stopped to chat. “Filia [the 4-year-old] has all the toilet paper, someone else has all the breakfasts, and Cami is carrying everyone’s sleeping bags,’’ he explained, later adding, “One of our goals is to encourage people do these things with their families.’’

It was hard to complain after meeting such a happy, ambitious family — led by a preschooler — on the trail. However, by day six, blisters and sore knees had taken their toll, and ibuprofen or “Vitamin I’’ as one woman called it, became the most coveted backcountry item. We had also become bored with our trail food, and began talking wistfully about our brush with civilization the next day, when we would pick up our next food cache and stop at Longmire’s restaurant and general store.

“I’m telling you, if they have it at Longmire, I’m getting it, whatever IT is,’’ said fellow hiker Sarah Hare.

Longmire serves as the park’s central hub, and has an information center, general store, small museum, inn, and restaurant with the world’s best burgers and beer (at least, they are after seven days of peanuts, dehydrated food, and some sort of vacuum-packed bread that won’t expire for two years).

We indulged in fresh salad, burgers, and beer, and then pressed on, glad to leave civilization behind and get back to the peacefulness of the forest. After one more epic day, a 14-mile grind along eroded ridges and through old-growth forests, we ended up at our last campsite, at Golden Lakes, by early afternoon. We spent the rest of the day reading, swimming, and floating on our sleeping mattresses in the middle of a lake. Then, despite rumors of rain, we slept without tents and stayed up late making shadow puppets on the tall trees around us.

Misty, foggy weather grabbed hold our final day, veiling the big mountain views. We reached the Mowich Lake trailhead by early afternoon, changed into sweet-smelling clothes, and then rattled down the pockmarked dirt road toward home. We toyed with the idea of stopping at a luxurious spa to soak in the hot tubs and get body scrubs, but decided to grab a burger and then beeline home to awaiting families.

“Besides,’’ said Stiles, “this trip was better than a whole week at the spa.’’

Kari Bodnarchuk can be reached at travelwriter@karib.us.