SnapshotUpdated May 2026
Cleanest Lakes
The highest-graded lakes in Minnesota and Wisconsin
Adams Lake in Vilas, WI is the cleanest lake with a TSI of -6 and an A grade.
| # | Name | Metric | Grade |
|---|---|---|---|
| 1 | Adams Lake Grade A, TSI -6 (oligotrophic), Vilas, WI | -6 | A |
| 2 | Clear Lake Grade A, TSI 8 (oligotrophic), Rock, WI | 8 | A |
| 3 | Sealion Lake Grade A, TSI 13 (oligotrophic), Florence, WI | 13 | A |
| 4 | Lily Lake Grade A, TSI 14 (oligotrophic), Marinette, WI | 14 | A |
| 5 | Crystal Lake Grade A, TSI 14 (oligotrophic), Oneida, WI | 14 | A |
| 6 | Clara Lake-Deep Hole Grade A, TSI 14 (oligotrophic), Lincoln, WI | 14 | A |
| 7 | Big Hurst Lake Grade A, TSI 14 (oligotrophic), Vilas, WI | 14 | A |
| 8 | Millicent Lake Grade A, TSI 15 (oligotrophic), Bayfield, WI | 15 | A |
| 9 | Roach Lake Grade A, TSI 15 (oligotrophic), Vilas, WI | 15 | A |
| 10 | Fountain Lake Grade A, TSI 15 (oligotrophic), Portage, WI | 15 | A |
Adams Lake in Vilas, WI is the cleanest lake with a TSI of -6 and an A grade.
Frequently Asked Questions
This report is auto-generated from real public data sources. Entities are ranked by their key metrics and the most notable changes and extremes are highlighted.
The underlying data is refreshed on a regular schedule. This report was generated from the most recent available data (last updated May 2026).
The primary metric varies by report type. It may represent a score, dollar amount, rate, or count depending on what the report is measuring.
Source: EPA National Aquatic Resource Surveys, 2026.