Last summer, local backcounty explorers Michael Donnelly and Alea Brager introduced me to the quixotic sport of "lake bagging."

A quasi-competitive activity concocted by Donnelly and a few friends during the mid-1980s, lake bagging is defined as visiting (and swimming in) as many mountain lakes as possible during the year's hottest months.

The rules are simple:

1) Every named lake counts as one lake bag. Unnamed lakes, ponds or pools can count as well, but only if they're deep enough to go over your head.

2) To achieve a "full bag" that can be added to your total, you must totally immerse yourself in the water (go for a swim, and dunk your head).

3) Pack out any garbage you find at the lake, and leave no trace.

4) If you're going to swim in your birthday suit, make sure there's nobody around who might be offended by a naked buttock or two.

The search for the best lake bagging territory often takes explorers deep into the backcountry — and sometimes off-trail — where many of the most beautiful and rewarding lakes can be found.

Now that we've entered the height of lake-bagging season, I thought I'd feature five of my favorite mountain lakes for swimming. All of these lakes are off the beaten track — in some cases way off the beaten track. A swim, after all, feels that much better if you've worked up a sweat.

Honorable Mention: Raspberry Lake

An emerald lake surrounded by white azaleas, filled with brook trout and nestled just below the Siskiyou Wilderness' highest peak, Raspberry Lake is the definition of a hidden gem.

It's an honorable mention because it's located across the southern border in extreme northwest California — and not technically in Oregon — but it will always be among my favorite places.

The trip requires a scenic 13.6-mile hike round-trip into the Siskiyou Wilderness. It makes a great place to backpack, and great day trips include climbing 7,313-foot Preston Peak and fishing for the lake's hungry rainbow trout.

The easiest route is via Young's Valley Trail. Once you reach the meadow surrounded by mountains, follow signs for Raspberry Lake. The hike is described in the book "Hiking Southern Oregon."

Directions: From Grants Pass, head southwest on Highway 199 a total of 47 miles, past Cave Junction and across the California border toward Crescent City, Calif. After passing through the Collier Tunnel, continue 3.5 miles and turn left onto Knopki Creek Road (Road 18N07). Follow this gravel road 14 miles — staying right at any questionable junctions — to the T junction with Forest Road 4803. Turn right onto Forest Road 4803 and follow the increasingly rough road 1 mile to a parking area. Trailhead coordinates: 41.8898, -123.654717

No. 5: Gifford Lake

As clear as Crater Lake and backed by Olallie Butte and Twin Peaks, this beautiful lake can be found at the end of an unmarked way trail in the Olallie Scenic Area northeast of Detroit.

Home to a campsite on a peninsula and any number of good places to dive in, Gifford Lake can be found by starting at Lower Lake Campground and following Fish Lake Trail 717 and Lodgepole Trail 706 to a way trail leading to Gifford Lake (The lake's coordinates are: 44.820612, -121.808730).

Directions: About a two-hour drive from Salem. Follow Highway 22 east to Detroit, and turn left on Breitenbush Road 46 for 28 miles. Turn right at signs for Olallie Lake and follow Forest Road 4220 to campground. Trailhead coordinates: 44.8231, -121.7956.

No. 4: Scout Lake

No matter what side of this lake you decide to jump into, chances are your view will be grand.

With the rounded cone of Park Butte rising on one side and Mount Jefferson on the other, this blue lake with sandy shores is a popular spot in one of the Central Cascades' most beautiful places.

The lake, and Jefferson Park, is most quickly reached via Whitewater Trailhead east of Detroit in the Mount Jefferson Wilderness. A hike of 11 miles round-trip and 1,800 feet of climb, the route qualifies as moderately difficult. Backpacking in Jefferson Park is very popular, so remember to only tent at designated sites.

Directions: About an hour-and-a-half drive from Salem. Follow Highway 22 east for 61 miles, passing Detroit. Between mileposts 60 and 61, turn left on Whitewater Road 2243. Follow this gravel route 7.4 miles to its end at a large parking area. Trailhead coordinates: 44.706730, -121.874899.

No. 3: Ice Lake / Ice Cube Lake

This pair of alpine lakes in the Eagle Cap Wilderness of northeastern Oregon's Wallowa Mountains are the definition of cold, pristine swimming.

Ice Lake is a spectacular destination popular with backpackers backed by the two tallest mountains in Eastern Oregon — the Matterhorn and Sacajawea Peak. Ice Cube Lake (not its official name) is a small snow tarn at 9,100 feet that forms in an alpine meadow surrounded by wildflowers in July and August with melting snow.

Both lakes, less than two miles apart, can be enjoyed as part of the classic Oregon climb to the summit of the 9,826-foot Matterhorn.

The route begins from Wallowa Lake Trailhead east of Joseph and climbs 3,400 feet and 8 miles to Ice Lake, then another 2,100 feet via a climbers' trail to the summit of the Matterhorn.

Ice Cube Lake can easily be seen during the climb, and a scramble trail leads down to its frozen, pure waters that will quite literally take your breath away. The entire trip requires 20.4 miles and 5,517 feet of climb. Lake coordinates: 45.228517, -117.291767.

Directions (to Wallowa Lake Trailhead): From La Grande and Interstate 84, follow Highway 82 east toward Wallowa Lake. Once you reach the entrance to the state park, veer left at the campground entrance and follow the paved road to a large parking area and trailhead. Trailhead coordinates: 45.26765, -117.212667.

No. 2: Lonesome Lake

How remote is this hidden pool surrounded by mountain azaleas deep in the Red Buttes Wilderness?

Well, the hike starts on a difficult-to-find trailhead in the Rogue River-Siskiyou National Forest. Then, on Fir Glade Trail, you hike across Oregon-California border, swing around spectacular Phantom Meadow on a ragged trail and drop down to Azalea Lake, a great place on its own, though not for swimming.

Finally, follow the even more ragged Fort Goff Trail 2 miles to a cutoff for Lonesome Lake on the right. Those who make the more than 20-mile round-trip journey are rewarded with a wonderful cliff where you can dive over the top of sweet-smelling azaleas into deep emerald water. But beware — a cougar calls this area home.

A map and description can be found in "Hiking Southern Oregon."

Directions: From Grants Pass, drive south on OR 238 for 18 miles to the green bridge at the town of Applegate. (From Medford, drive to Jacksonville and then follow OR 238 to Applegate.) Just before the green bridge over the Applegate River, turn south onto Thompson Creek Road and proceed 12 miles to a gravel hilltop amid a maze of side roads. Continue straight, ignoring the two roads on the right, through the intersection for 2.8 miles on gravel Carberry Creek Road (CR 777). Turn right across a bridge onto FR 1030, following a ragged Fir Glade marker (that may have come down). Follow FR 1030 for 5 miles along a creek; turn left onto Spur 400 and proceed for another 5 miles. Eventually the road crests and becomes FR 1040. Just beyond the gap, turn right onto the rugged Spur 800 for 0.6 mile and fork left into a small parking lot. Trailhead coordinates: 42.005533, -123.290233.

No. 1: Little Strawberry Lake

Surrounded by a cathedral of red and silver stone, this spectacular lake in the Strawberry Mountains of Eastern Oregon checks every box on the lake bagging wish list.

It takes a long drive into the canyon lands near John Day to reach the Strawberry Mountain Wilderness. From Strawberry Campground, outside Prairie City, a trail leads 2 miles to more famous Strawberry Lake and then another 2 miles to Little Strawberry. (It can also be made part of an outstanding 15- to 18-mile backpacking trip).

Within this glacial basin of red and silver peaks, hop over to a landslide where high piles of rock make a natural diving board to "bag" my favorite lake in Oregon.

Directions toStrawberry Campground Trailhead. From Prairie City on Highway 26, turn right onto Main Street and follow it to Bridge Street. Follow the pointers for Strawberry Campground south onto Strawberry Road for 10 miles to its end at the campground. Coordinates: 44.3193, -118.67395.

Zach Urness has been an outdoors writer, photographer and videographer in Oregon for six years. He is the author of the book "Hiking Southern Oregon" and can be reached at zurness@StatesmanJournal.com or (503) 399-6801. Find him on Facebook at Zach's Oregon Outdoors or @ZachsORoutdoors on Twitter.