These 5 Secret Lakes In The US Are Unbelievably Clean And Clear

There are over 3 million lakes in the United States, with the vast majority of them in Alaska. Visit any of them and you'll find a wide range of outdoor activities available to you on land and in the water. When you're planning a lakeside holiday, you'll see lists praising clean and clear lakes in particular. A lake's cleanliness is usually measurable, often depending on the amount of pollutants in the water — a highly polluted lake will be unsafe for swimming. A lake's clarity, meanwhile, is simply a measure of how clear the water is. Murky water doesn't necessarily mean the lake is dirty, but you can see for dozens of feet underwater in a clear lake.

A variety of factors can affect water conditions, from naturally occurring phenomena to human activity. One thing is certain: A clean and clear lake will likely attract thousands of travelers every season, often turning it into an overcrowded destination that may not be the relaxing retreat you're looking for. Taking into account the latest data and recommendations from travelers, we want to introduce you to five lesser-known lakes with clean and clear waters across the U.S.

Only an hour-and-a-half drive from downtown Boston and situated in the foothills of Mount Sunapee and Mount Kearsarge, Lake Sunapee is one of New Hampshire's best-kept secrets. It's smaller and quieter than Lake Winnipesaukee, New Hampshire's largest lake, and by far a less crowded destination. With 70 miles of shoreline and clear waters that allow a peek at the aquatic life up to 30 feet under, according to Lake.com, Lake Sunapee is a paradise for those itching to sail or go powerboating. Several peninsulas and 11 islands make the view of the lake and its surroundings especially awe-inspiring. 

The water quality is continuously tested by the Lake Sunapee Protective Association, which has assessed that the waters remain at "Class A" levels to this day — that's good enough to swim in and even drink when treated properly. 

Visitors can enjoy lakeside fun at two beaches, Lake Sunapee State Beach and Dewey Beach. Late spring and summer are the best seasons to visit and go for a swim, though you can enjoy the lakeside year-round. The lake itself is surrounded by state parks with tons of trail options for hiking enthusiasts. Birdwatchers are encouraged to visit to try and spot some of the area's feathered residents at the John Hay National Wildlife Refuge, home to some of New England's most enchanting gardens, where you can walk along a series of nature trails and see exhibits at the ecology center.

Big Bear Lake in California is one of the most filmed lakes in the world, yet many travelers, including the experts at Fodor's, consider it to be a hidden gem. Situated in the San Bernardino Mountains at around 7,000 feet above sea level, according to Lake.com, Big Bear Lake rewards travelers who go the distance with ultra-clear waters — pristine conditions for fishing, especially. It's one of the more well-known lakes on this list, mainly because it's a public lake and is very accessible to anybody visiting the area, but don't let that discourage you.

Big Bear Lake is most popular with kayakers and waterboarders, but there are also tons of family-friendly activities along the lake's shore, including the Big Bear Alpine Zoo, which acts as the main rehabilitation center for wounded or imprinted wildlife in the area. Visitors can also enjoy the area's ample hiking trails, including the 1.5-mile trek up to Castle Rock Peak and the 4.8-mile Cougar Crest Trail, or head to Boulder Bay Park for more recreation opportunities. A walk around the village will introduce you to local businesses and great eateries for a quick bite.

Lake.com also named Big Bear Lake as the sunniest lakeside destination in the United States. The report reveals that "the city averages 33% more direct sunlight than the state's most populated city, Los Angeles," or 335.02 watts per square meter. Soaking up the sun while keeping cool has never proved easier.

Experienced travelers praise Flathead Lake for being an often-overlooked lake, and Lake.com has specifically praised it for its remarkably clean water — the Montana destination ranked at No. 10 on the website's list of the cleanest lakes in the United States. Those boating or paddling on the lake can see up to 20 feet deep into the aquamarine waters underneath.

Clean and clear waters are but one of the attractive elements of Flathead and its surrounding towns. The region has also piqued the interest of wine lovers as an up-and-coming wine region. Montana is not the state that usually comes to mind when thinking of American wine, but a surge of new wineries is changing the game.

Flathead Lake's water quality has been closely monitored for over 100 years, with efforts led by the Flathead Lake Biological Station (FLBS). The lake has managed to maintain near-perfect quality, making it one of the cleanest in the world, according to the FLBS, but there is a looming threat. Increased activity around the lake could expose the water to dangerous pollutants, directly impacting the water quality if necessary precautions are not taken.

Lake Chelan ranked second on Lake.com's list of the cleanest lakes in the country after Lake Superior. Situated in Washington State, this is the third-deepest lake in America at nearly 1,500 feet deep. It snakes along the Okanogan-Wenatchee National Forest, its shore totaling 109.17 miles in length. The clarity and quality here are heavily attributed to the glaciers that feed its waters. Dense bushes aren't the only thing you'll find along the shores of Lake Chelan — orchards and vineyards make the landscape especially beautiful. 

The Lake Chelan State Park is also located along the shores of the eponymous lake, and here visitors can indulge in hiking, camping, and birdwatching. Back on the water, the usual activities are available: boating or sunbathing on sandy beaches. Anglers are particularly spoiled for choice. Locals claim the lake allows for some of the best fishing you can do in Washington state, and Best Fishing America named Lake Chelan as one of the best places to catch big kokanee salmon and lake trout in the entire Pacific Northwest.

Idaho's largest lake may not be the first to come to mind when you think of a clean and clear lake, but Lake Pend Oreille has ultra-clear waters and a solid 2.09 out of 10 on the pollution score, making it the fifth-cleanest lake in the United States according to Lake.com. Pend Oreille is 43 miles long with a shoreline that stretches 111 miles, and at 1,158 feet deep, according to Visit North Idaho, it's the deepest lake in Idaho and the fifth-deepest in the country, too. 

Clean and ultra-clear waters only complement the region's natural splendor. Visitors can see as deep as 150 feet when the water is in its best conditions, providing the best visibility of any lake on this list. As the lake is located along the Rocky Mountains, snowy peaks reflect in the water during the colder months, while rolling green hills paint the landscape in the spring and summer. It's a perfect backdrop to your fishing or boating trip.

In addition to amazing water recreation and lakeside opportunities, Pend Oreille thrives in the panhandle as a recreational paradise surrounded by artsy towns, including Sandpoint, Hope, Clark Fork, and Bayview, to name a few. Each of these communities boasts unique activities, shops, and experiences imbued with charm.

Clear water doesn't always equal clean water. For this list, lakes that ticked both of those boxes were prioritized, providing awesome views as well as dipping opportunities for maximum enjoyment and rewards. The list includes lakes that don't always come to mind when we think of clean or clear waters — that brain space is usually reserved for big-name lakes like Lake Tahoe.

Data from Lake.com's 2025 report on the cleanest (and dirtiest) lakes in America, as well as other authoritative sources, were used to identify the lakes with up-to-date data, using pollution as the main metric. Then, lists curated by well-traveled lake enthusiasts were cross-checked to confirm that these nominations were, in fact, still relevant to anyone planning a trip in the near future. 

Travelers should remember that water clarity and quality can vary depending on the season, aquatic life, and human activity. Even extremely clean lakes and beaches can be contaminated or stricken with outbreaks of algae, and it can happen suddenly! Be sure to check official sources for the latest advisories, if there are any, and information.