Scientists have compiled a nationwide guide that identifies the single clearest lake in each U.S. State, using documented Secchi‑disk transparency data, long‑term monitoring programs, oligotrophic classifications and recognition from state or federal agencies.
National Clarity Leaders: 20 Lakes That Rise Above the Rest
Crater Lake – Oregon
Crater Lake in southern Oregon’s Cascade Range records Secchi depths that have exceeded 100 feet (30 m) and historically surpassed 130 feet (40 m). Formed in a collapsed volcano and fed only by snow and rain, the lake’s lack of river inflow limits sediment and nutrients, contributing to its sapphire‑blue clarity.
Lake Tahoe – California and Nevada
Lake Tahoe straddles the Sierra Nevada and averages Secchi depths around 60 feet (18 m) while plunging to 1,645 feet (501 m). Granite bedrock, cold alpine conditions and decades of watershed protection sustain its vivid blue water, making it the clearest large lake cited by both states.
Lake Chelan – Washington
Lake Chelan stretches 50 miles (80 km) through a glacial valley and is classified as ultra‑oligotrophic, keeping nutrient levels low and water exceptionally clear. Its deep, fjord‑like basins and minimal sediment inflow preserve cold, transparent water.
Flathead Lake – Montana
Flathead Lake, the largest natural freshwater lake west of the Mississippi, regularly participates in Secchi Dip‑In monitoring, with seasonal visibility of 20–30 feet (6–9 m). Fed by glacial waters near Glacier National Park, its depth and low nutrient input support strong transparency.
Lake George – New York
Framed by the Adirondacks, Lake George frequently records Secchi depths over 20 feet (6 m) and occasionally exceeds 30 feet (9 m). Granite geology, limited development and ongoing monitoring protect its long‑standing clarity.
Jordan Pond – Maine
Jordan Pond in Acadia National Park is Maine’s clearest lake, classified as oligotrophic and used as a drinking‑water source. Strict protection allows visibility to stretch far from shore on calm days.
Torch Lake – Michigan
Glacial origins and a pale sandy bottom deliver Torch Lake striking turquoise water, with Secchi transparency often over 20 feet (6 m) in calm summer conditions. It stands as Michigan’s clearest large lake.
Lake Jocassee – South Carolina
Lake Jocassee, tucked in the Blue Ridge foothills, offers divers visibility of 30–50 feet (9–15 m). Forested slopes, limited shoreline development and deep mountain water facilitate maintain this clarity.
Summersville Lake – West Virginia
Nicknamed “The Little Bahamas of the East,” Summersville Lake’s bright blue water and rocky shorelines produce exceptional visibility. Its relatively undeveloped surroundings contribute to its reputation for clarity.
Black Oak Lake – Wisconsin
Black Oak Lake records some of the highest Secchi depths in Wisconsin, thanks to its glacial origins, limited shoreline disturbance and forested watershed. It serves as the state’s most consistently measured clarity benchmark.
Amistad Reservoir – Texas
On the Texas‑Mexico border, Amistad Reservoir is noted for clear blue water and high underwater visibility, frequently ranking among the state’s clearest large reservoirs.
Wilson Lake – Kansas
Wilson Lake’s rocky shoreline and deep, blue water give it a reputation as Kansas’s clearest lake, with limited sediment input enhancing visibility.
Bear Lake – Utah and Idaho
Bear Lake, straddling Utah and Idaho, is celebrated for its striking sapphire‑blue water and high transparency, a hallmark of the surrounding Uintah Basin.
Jenny Lake – Wyoming
At the base of the Teton Range, Jenny Lake reflects alpine clarity and cold oligotrophic conditions, revealing underwater rocks on calm days.
Newfound Lake – New Hampshire
Newfound Lake consistently ranks among New Hampshire’s clearest lakes, supported by strong water‑quality monitoring and deep, cold basins.
Lake Willoughby – Vermont
Framed by steep cliffs, Lake Willoughby’s glacial depth and cold water preserve remarkable transparency, making it Vermont’s clarity standout.
Lake Ouachita – Arkansas
Lake Ouachita’s rocky basin and protected setting within the Ouachita National Forest sustain visibility that often exceeds 20 feet (6 m). Sparse shoreline development keeps nutrient input low.
Broken Bow Lake – Oklahoma
Located in the Ouachita Mountains, Broken Bow Lake’s steep terrain and limited development reduce sediment inflow, enhancing underwater visibility.
Norris Lake – Tennessee
Norris Lake’s deep, winding coves and relatively low nutrient levels support strong transparency across much of the reservoir.
West Okoboji Lake – Iowa
West Okoboji Lake is a deep glacial lake whose cold, blue water sets the state’s clarity benchmark.
The Clearest Lake in the Remaining 28 States
Alabama – Lewis Smith Lake
Lewis Smith Lake’s deep, rocky basins and consistent visibility earn it the title of Alabama’s clearest lake, with divers noting glassy blue water in less developed arms.
Alaska – Kenai Lake
Kenai Lake on the Kenai Peninsula combines glacially fed turquoise water with strong visibility, making it Alaska’s most recognized large clear lake.
Arizona – Knoll Lake
High on the Mogollon Rim, Knoll Lake stands out for unusually clean and clear water compared with many desert reservoirs.
Colorado – Hanging Lake
Hanging Lake’s glass‑clear travertine water in Glenwood Canyon is strictly protected to preserve its pristine condition.
Connecticut – Powers Lake
Powers Lake in western Connecticut is locally described as one of the state’s cleanest lakes, benefiting from limited development.
Delaware – Killens Pond
Killens Pond State Park hosts one of Delaware’s clearer inland waters, recognized for its visual clarity.
Florida – Crescent Lake
Spring influence and comparatively low turbidity set Crescent Lake apart from many nutrient‑rich Florida lakes, maintaining some of the state’s clearest natural conditions.
Georgia – Lake Allatoona
Lake Allatoona’s rocky shoreline and managed reservoir conditions often produce clearer water than many other Georgia lakes.
Hawaii – Lake Waiau
Lake Waiau, perched on Mauna Kea, is one of Hawaii’s few natural lakes and features notably clear alpine water.
Illinois – Lake Le‑Aqua‑Na
Lake Le‑Aqua‑Na, a small state‑park lake in northwestern Illinois, is frequently labeled one of the state’s cleanest, and clearest.
Indiana – Clear Lake
Clear Lake in northeastern Indiana lives up to its name and is widely regarded as the state’s clearest natural lake.
Kentucky – Laurel River Lake
Within the Daniel Boone National Forest, Laurel River Lake’s deep blue‑green water is frequently cited as Kentucky’s clearest reservoir.
Louisiana – Lake Claiborne
Lake Claiborne in north‑central Louisiana is often described as the state’s clearest lake.
Maryland – Greenbrier Lake
Greenbrier Lake in western Maryland’s Greenbrier State Park enjoys a reputation for clarity thanks to its sandy beach and relatively clean water.
Massachusetts – Joshua Pond
Joshua Pond on Cape Cod is widely praised for its unusually clear, clean water.
Mississippi – Clear Springs Lake
Spring‑fed conditions and a light‑colored lake bottom enhance visibility at Clear Springs Lake in the Homochitto National Forest.
Minnesota – Caribou Lake
Caribou Lake in Itasca County is known for striking transparency, with water appearing almost window‑clear along sandy and rocky edges.
Missouri – Table Rock Lake
Table Rock Lake’s rocky Ozark shoreline supports good underwater visibility in the central Missouri landscape.
Nebraska – Bridgeport State Recreation Area Lake
This sand‑pit lake in western Nebraska is frequently described as the state’s clearest due to its strikingly blue water.
New Jersey – Atsion Lake
Located in the Pine Barrens, Atsion Lake is often regarded as one of New Jersey’s clearest lakes.
New Mexico – Lake Katherine
High in the Sangre de Cristo Mountains, Lake Katherine features cold, exceptionally clear mountain water.
North Carolina – White Lake
Spring‑fed White Lake in Bladen County is widely touted as North Carolina’s clearest natural lake.
North Dakota – Lake Upsilon
Lake Upsilon, a spring‑fed glacial lake near the Canadian border, is known for unusually clear, turquoise water.
Ohio – Nelson Ledges Quarry
Nelson Ledges, a former quarry turned swimming lake in northeastern Ohio, is prized for its deep, clear water.
Pennsylvania – Raystown Lake
Raystown Lake benefits from a large basin and relatively low shoreline development, producing clearer coves during stable summer weather.
Rhode Island – Wallum Lake
Wallum Lake along the Massachusetts border is recognized for high water quality and good clarity.
South Dakota – Sylvan Lake
Sylvan Lake in Custer State Park sits in a granite‑ringed basin that keeps the water crisp and bright on clear days.
Virginia – Lake Moomaw
Lake Moomaw in the Alleghany Highlands benefits from limited shoreline development, preserving transparency in its rocky coves.
Where Clarity Endures
Across the United States, the clearest lakes share traits such as depth, cold temperatures, rocky or spring‑fed origins and protection within forests or managed watersheds. Low nutrient input and limited shoreline disturbance allow sunlight to penetrate far below the surface, making water clarity a reliable indicator of ecological balance.
Looking ahead, continued monitoring could guide stewardship efforts, while heightened public awareness may boost responsible recreation and support for protection policies. Analysts expect that states may prioritize funding for watershed management to preserve these clear‑water assets, and tourism operators could promote these lakes as destinations for eco‑friendly visitors.
Frequently Asked Questions
What is a Secchi disk and how is it used?
A Secchi disk is a simple black‑and‑white plate lowered into the water to measure the depth at which it remains visible; the deeper the disk stays in view, the clearer the lake.
Why does water clarity matter?
Clarity reflects low nutrient levels, limited sediment runoff, protected watersheds and careful stewardship, indicating overall ecological health.
How were the clearest lakes selected for each state?
The guide relied on documented transparency reporting, long‑term monitoring programs, oligotrophic classifications tied to clarity data, and recognition supported by state or federal agencies.
Which lake’s clarity do you identify most surprising, and why?
