Published March 24, 2026 · Updated August 18, 2026
The Clearest Lake in Every County We Track
Across 1,277 counties in the 49 states and 2 Canadian provinces with a Secchi reading, 140 county champions clear 20 feet of visibility and 469 never reach 4. A county title is a local maximum, not a national one.
The clearest county champions
The current head of this list is Adams Lake in Vilas County, WI, at 100 feet of Secchi depth. Secchi is a field measurement of how far a black-and-white disk stays visible — see Water Clarity Explained and the Secchi depth guide. It is not the letter grade. The national Secchi roundup is Clearest Lakes in America.
| Rank | County | State | Clearest lake | Clarity (ft) | Grade |
|---|---|---|---|---|---|
| 1 | Vilas | WI | Adams Lake | 100 | NR |
| 2 | Parry Sound District | ON | Cadden Lake | 57.4 | A |
| 3 | Meade | KS | Meade Lake | 53 | NR |
| 4 | Thunder Bay District | ON | Greenwater Lake | 47.9 | A |
| 5 | St. Louis | MN | St James Pit Lake | 47.6 | NR |
| 6 | Sublette | WY | Fremont Lake | 42.8 | B |
| 7 | Sudbury District | ON | George Lake | 42.7 | A |
| 8 | Klamath | OR | Crescent Lake | 42.2 | A |
| 9 | Nipissing District | ON | Kearney Lake | 41 | A |
| 10 | Johnson | WY | Lake Desmet Lpd | 39.1 | B |
| 11 | Frontenac | ON | Blue Lake | 37.7 | A |
| 12 | Algoma District | ON | Basswood Lake | 37.7 | A |
| 13 | Lincoln | MT | Big Therriault Lake | 37.3 | NR |
| 14 | Rutland | VT | Sunset Lake | 36.1 | A |
| 15 | Kenora District | ON | Sandford Lake | 34.8 | A |
| 16 | Chippewa | MI | Whitefish Bay Deep Lake | 34.4 | NR |
| 17 | Roscommon | MI | Higgins Lake | 34 | NR |
| 18 | Bonaventure | QC | Lac de la Ferme | 33.5 | A |
| 19 | Matawinie | QC | Lac Couture | 33.3 | A |
| 20 | Flathead | MT | Ashley Lake | 33.1 | NR |
When the county champion is still murky
At the other end, the county whose “clearest” lake is still only 0.2 feet is Jefferson County, NE — Cub Creek Lake. That is the more honest local story in farm-belt and prairie counties: even the winner may be a green basin. A 3-foot county champion is a signal to read the county ranking before booking a swim.
| County | State | Clearest lake | Clarity (ft) | Grade |
|---|---|---|---|---|
| Jefferson | NE | Cub Creek Lake | 0.2 | NR |
| Johnston | OK | Lake Texoma | 0.3 | NR |
| Adams | NE | Lake Hastings | 0.3 | NR |
| Cloud | KS | Jamestown Wildlife Area Lake | 0.4 | F |
| Grayson | TX | Lake Texoma | 0.4 | NR |
| Harper | KS | Anthony City Lake | 0.4 | F |
| La Crosse | WI | Neshonoc Lake | 0.4 | NR |
| McClain | OK | Wiley Post Memorial Lake | 0.5 | NR |
| Kingman | KS | Kingman Co State Fishing Lake | 0.6 | NR |
| Henry | MO | Montrose Lake | 0.6 | F |
| Cotton | OK | Dave Boyer Lake | 0.6 | NR |
| Woodward | OK | Fort Supply Lake | 0.6 | NR |
| Chesapeake city | VA | Lake Drummond Sta Mid | 0.7 | C |
| Abitibi-Ouest | QC | Lac Abitibi | 0.7 | D |
| Crosby | TX | White River Lake | 0.7 | D |
One champion per state
Collapse the county list to the single clearest county-winner in each state and the geology shows through: northern forest and mountain states send 20-foot lakes; plains states often send single-digit ones. For a grade-based (not Secchi-based) pick in every county, use best lake in every county.
38 states and provinces appear in that table. For the clearest lakes nationally, with no one-per-county limit, see the clearest-lakes ranking.
Frequently Asked Questions
For each of 1,277 counties with a clarity reading, this page names the single clearest measured lake. The clearest of all the county winners is Adams Lake in Vilas County, WI, at 100 feet. For the best lake in each county by water-quality grade rather than clarity, see lakequality.org/ranking/best-by-county.
No. It is a local maximum. A county whose champion is 4 feet of Secchi is telling you something about the whole county. A county whose champion is 30 feet may still be full of green ponds. Read the county page, not just the winner.
No. Secchi measures how far light penetrates. Tannin-stained bog lakes are dark and often nutrient-poor. Clay-turbid reservoirs can be low-algae and still murky. The letter grade is a nutrient-and-algae score; Secchi is reported, not scored. See Water Clarity Explained.
There are 1,277 counties with a clarity champion — too many to read through in one sitting. This page shows the clearest and murkiest ends of that list plus the best lake in each state, and each county has its own page with all of its lakes.
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