Clearest Lakes in Ontario
Of the 868 lakes measured since 2015, the clearest is Basswood Lake, where a Secchi disc stayed visible to 11.1 m (2025). The median reading is 3.6 m.
Distribution
Number of lakes in each range (m), out of 868.
How this is measured
Clarity is the season’s mean Secchi depth, the depth at which a black-and-white disc lowered into the water disappears, measured by volunteers (Ontario Lake Partner Program; Quebec Réseau de surveillance volontaire des lacs). Only lakes measured in 2015 or later are ranked; the year is shown. Clarity varies from year to year with algae and dissolved organic matter, and very clear water can mean few nutrients, not cleaner water.
Data as of October 9, 2026.
Top 100
| # | Lake | Secchi depth m | Max depth m | Area km² |
|---|---|---|---|---|
| 1 | Basswood LakeAlgoma | 11.1 (2025) | 73 | 27 |
| 2 | Quirke LakeAlgoma | 9.2 (2025) | 102 | 20.7 |
| 3 | Watersnake LakeCochrane | 9.1 (2024) | 6 | 1.04 |
| 4 | Clean LakeHaliburton | 9 (2015) | 43 | 1.58 |
| 5 | Lake ClearRenfrew | 8.9 (2025) | 37 | 17.5 |
| 6 | Macdonald LakeHaliburton | 8.5 (2015) | 40 | 1.4 |
| 7 | Louie LakeHaliburton | 8.3 (2015) | 40 | 0.33 |
| 8 | Salmon LakePeterborough | 8.3 (2024) | 29 | 1.82 |
| 9 | Hook LakeAlgoma | 8.2 (2018) | 0.22 | |
| 10 | Mississagagon LakeFrontenac | 8.2 (2025) | 5.39 | |
| 11 | Lowell LakeNipissing | 8 (2017) | 0.94 | |
| 12 | McGowan LakeParry Sound | 7.9 (2025) | 0.2 | |
| 13 | Charleston LakeLeeds and Grenville | 7.8 (2025) | 90 | 26.9 |
| 14 | Green LakeRenfrew | 7.7 (2024) | 0.82 | |
| 15 | Fairbank LakeGreater Sudbury / Grand Sudbury | 7.7 (2025) | 43 | 7.05 |
| 16 | Mohan LakeParry Sound | 7.5 (2024) | 0.17 | |
| 17 | Nelson LakeGreater Sudbury / Grand Sudbury | 7.4 (2016) | 49 | 3.09 |
| 18 | Clinto LakeHaliburton | 7.4 (2015) | 1.41 | |
| 19 | Burdock LakeHaliburton | 7.4 (2025) | 11 | 0.15 |
| 20 | Arnott LakeAlgoma | 7.3 (2018) | 2.42 | |
| 21 | Matinenda LakeAlgoma | 7.3 (2025) | 85 | 41.5 |
| 22 | Lake TemagamiNipissing | 7.2 (2024) | 73 | 240 |
| 23 | Lake KagawongManitoulin | 7.2 (2025) | 34 | 56.2 |
| 24 | Arrow LakeThunder Bay | 7.2 (2025) | 49 | 32.5 |
| 25 | Farquhar LakeHaliburton | 7.1 (2023) | 3.46 | |
| 26 | Forget LakeParry Sound | 7.1 (2024) | 0.27 | |
| 27 | Palmerston LakeFrontenac | 7.1 (2024) | 55 | 5.62 |
| 28 | Lauzon LakeAlgoma | 7.1 (2025) | 79 | 22.1 |
| 29 | Margaret LakeMuskoka | 7.1 (2025) | 0.57 | |
| 30 | Portage LakeGreater Sudbury / Grand Sudbury | 7 (2024) | 0.39 | |
| 31 | Charlotte LakeRenfrew | 7 (2018) | 24 | 1.13 |
| 32 | Trout LakeRenfrew | 7 (2025) | 43 | 1.82 |
| 33 | Windy LakeGreater Sudbury / Grand Sudbury | 7 (2024) | 55 | 11.4 |
| 34 | Matagamasi LakeGreater Sudbury / Grand Sudbury | 7 (2024) | 52 | 13.2 |
| 35 | Six Mile LakeMuskoka | 7 (2025) | 13.9 | |
| 36 | Lonely LakeAlgoma | 6.9 (2018) | 2.9 | |
| 37 | Faris LakeParry Sound | 6.9 (2023) | 15 | 0.17 |
| 38 | Bass LakeLeeds and Grenville | 6.9 (2023) | 24 | 0.99 |
| 39 | Camp LakeCochrane | 6.8 (2025) | 2.77 | |
| 40 | Farren LakeLanark | 6.8 (2025) | 21 | 1.76 |
| 41 | Belmont LakePeterborough | 6.8 (2022) | 16 | 7.85 |
| 42 | L'Amable LakeHastings | 6.7 (2017) | 34 | 1.75 |
| 43 | Brule LakeFrontenac | 6.7 (2025) | 55 | 5.81 |
| 44 | Raft LakeGreater Sudbury / Grand Sudbury | 6.7 (2016) | 16 | 1.29 |
| 45 | Ardoch LakeFrontenac | 6.7 (2025) | 17 | 0.9 |
| 46 | Kukagami LakeSudbury | 6.6 (2025) | 55 | 18.9 |
| 47 | Silver LakeFrontenac | 6.6 (2017) | 22 | 2.5 |
| 48 | Aylen LakeNipissing | 6.5 (2024) | 67 | 21.2 |
| 49 | Goodwin LakeHaliburton | 6.5 (2015) | 24 | 0.56 |
| 50 | Clear LakeParry Sound | 6.5 (2025) | 47 | 2.25 |
| 51 | Oak LakePeterborough | 6.5 (2022) | 22 | 2.88 |
| 52 | Bass LakeLeeds and Grenville | 6.5 (2025) | 2.96 | |
| 53 | Four Mile LakeKawartha Lakes | 6.5 (2025) | 18 | 7.56 |
| 54 | Mindemoya LakeManitoulin | 6.5 (2025) | 18 | 38.1 |
| 55 | Grandview LakeMuskoka | 6.4 (2025) | 26 | 0.74 |
| 56 | Flaxman LakeParry Sound | 6.4 (2023) | 24 | 0.63 |
| 57 | Stormy LakeHaliburton | 6.4 (2024) | 26 | 1.01 |
| 58 | McCarrel LakeAlgoma | 6.4 (2024) | 42 | 1.98 |
| 59 | Wolfe LakeFrontenac | 6.4 (2025) | 10 | |
| 60 | Nettie LakeTimiskaming | 6.3 (2025) | 35 | 0.5 |
| 61 | Mephisto LakeHastings | 6.3 (2023) | 1.7 | |
| 62 | Carson LakeRenfrew | 6.3 (2025) | 43 | 2.7 |
| 63 | Halls LakeHaliburton | 6.3 (2025) | 73 | 5.33 |
| 64 | Knowlton LakeFrontenac | 6.3 (2024) | 35 | 1.96 |
| 65 | Hawk LakeKenora | 6.3 (2025) | 8.91 | |
| 66 | Big Hawk LakeHaliburton | 6.2 (2025) | 52 | 3.95 |
| 67 | Canonto LakeFrontenac | 6.2 (2025) | 21 | 2.29 |
| 68 | Dunlop LakeAlgoma | 6.2 (2025) | 49 | 10.4 |
| 69 | Lake ManitouManitoulin | 6.2 (2025) | 49 | 106 |
| 70 | Camp LakeMuskoka | 6.2 (2025) | 48 | 2.39 |
| 71 | Cross LakeNipissing | 6.2 (2024) | 55 | 17.9 |
| 72 | Trout LakeParry Sound | 6.1 (2019) | 2.28 | |
| 73 | Marl LakeBruce | 6.1 (2024) | 0.16 | |
| 74 | Kernick LakeParry Sound | 6.1 (2019) | 0.48 | |
| 75 | Crane LakeParry Sound | 6.1 (2025) | 34 | 5.66 |
| 76 | Grindstone LakeFrontenac | 6.1 (2023) | 20 | 1.61 |
| 77 | Mosque LakeFrontenac | 6.1 (2025) | 31 | 1.55 |
| 78 | Picard LakePeterborough | 6.1 (2025) | 34 | 0.77 |
| 79 | Ashby LakeLennox and Addington | 6.1 (2025) | 37 | 2.61 |
| 80 | Moose LakeHaliburton | 6.1 (2019) | 46 | 2.96 |
| 81 | Tory LakeHaliburton | 6 (2025) | 16 | 0.21 |
| 82 | Clark LakeHastings | 6 (2025) | 0.42 | |
| 83 | Loughborough LakeFrontenac | 6 (2025) | 34 | 19.4 |
| 84 | Clear LakeHaliburton | 6 (2025) | 55 | 0.32 |
| 85 | Himbury LakeParry Sound | 6 (2025) | 0.51 | |
| 86 | McFadden LakeHaliburton | 6 (2015) | 31 | 0.58 |
| 87 | Colton LakeRenfrew | 6 (2018) | 0.78 | |
| 88 | Buzzard LakePeterborough | 6 (2024) | 37 | 0.95 |
| 89 | Island LakeParry Sound | 6 (2025) | 1.31 | |
| 90 | Rib LakeTimiskaming | 6 (2025) | 43 | 6.83 |
| 91 | Champlain Trail LakesRenfrew | 6 (2021) | 64 | 15 |
| 92 | Skeleton LakeMuskoka | 6 (2024) | 75 | 20.7 |
| 93 | Silver LakeKenora | 6 (2019) | 82 | 25.9 |
| 94 | Jumping Cariboo LakeNipissing | 6 (2017) | 4.51 | |
| 95 | Miskwabi LakeHaliburton | 6 (2025) | 43 | 3.45 |
| 96 | Simmons LakeParry Sound | 5.9 (2023) | 0.39 | |
| 97 | Dempseys LakeRenfrew | 5.9 (2025) | 0.59 | |
| 98 | Emsdale LakeParry Sound | 5.9 (2025) | 18 | 0.68 |
| 99 | Munro LakeCochrane | 5.9 (2024) | 1.13 | |
| 100 | Animoosh LakeNipissing | 5.9 (2017) | 0.62 |
Other rankings
- Deepest lakes2,688
- Largest lakes18,731