Opal Pool1 of 6
Tucked away inside Oregon's magical Opal Creek Wilderness Area (one of the last low-elevation old growth forests left in the Pacific Northwest), Opal Pool is a special find. Though this swimming hole is by no means a secret, the 7-mile round-trip hike to reach it helps deter some of the crowds. You'll be glad you made the hike, however, when you submerge yourself in Opal Pool's magical turquoise waters or cliff jump from the basalt rock that rises far above it. After your swim, visit nearby Jawbone Flats, an abandoned mining camp that is now home to the off-the-grid Opal Creek Ancient Forest Center.
Lower Lewis River Falls2 of 6
When Portlanders seek to escape the heat they head to Lower Lewis River Falls, located just north of the city in Washington State. This swimming hole was created from the force of the powerful waterfall that has, over time, eroded a plunge pool in the river. On hot summer days, daredevils line up to jump into the pool from the cliffs above. If you prefer to keep your feet on the ground (or at least in the river), the area surrounding the it is shallow and perfect for sitting or wading.
Photo/Chris Weber, Flickr
Lost Lake3 of 6
It's hard to imagine a scene more idyllic than the one at Lost Lake. Picture an 85-acre alpine lake ringed in old-growth forest. Rising above it, Oregon's most famous mountain, snowcapped Mt. Hood, reflects in the shimmering waters. Hikers can work up a sweat on the 3.4-mile lakeshore trail that circumnavigates the lake before diving into the pristine (but cold!) waters. Pro tip: Pack a blow-up inner tube and float the day away in one of Oregon's most beautiful spots.
Rooster Rock State Park4 of 6
Do you want to make your dip in the outdoors a little more, ahem, natural? Then take a drive to Rooster Rock State Park in the Columbia River Gorge. There are two swimming beaches here, and one of them is clothing optional (it's one of only two designated nude beaches in the entire state). For those of us who enjoy the beach with our bathing suits on, Rooster Rock State Park also has a large clothing-required beach. If you plan to bring the kids (or the shy), note that the nude beach is not visible from the traditional beach, so everyone can swim in harmony.
Whittaker Creek Recreation Area5 of 6
Located west of Eugene near Walton, Oregon, Whittaker Creek Recreation Area is a great place to take a cold dip on a hot day while also exploring Oregon's Coast Range. Lightly trafficked, even in the hottest months, Whittaker Creek has both a swimming beach and access to the Siuslaw River (don't swim in the river though--it has Class II and Class III rapids). When you've cooled off, check out the popular wildlife viewing area or pitch a tent at one of the nearby campsites.
Photo/Bureau of Land Management Oregon and Washington, Flickr