Fawn Lake
Adams County, WisconsinMesotrophic
Fawn Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
Mesotrophic conditions dominate at Fawn Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. At 19 acres, Fawn Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within Adams County's 19 graded lakes, Fawn Lake ranks 10 — below the local median, though not at the bottom.
No invasive species are currently listed at Fawn Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Fawn Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-15. Grade methodology: LakeGrade methodology.
Watch Fawn Lake water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 20.4 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | C |
| Phosphorus | 20.4 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 19 acres |
| Public Access | Yes |
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.286 m/yr | 7 |
| Phosphorus | → Stable | +0.16 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #10 of 19 lakes in Adams County
Cleaner Lakes Within 30 Miles
Fawn Lake holds Grade B. 4 nearby lakes hold higher grades.
- ADeep LakeAdams County · mi · Higher grade (B → A)
- AParker LakeAdams County · mi · Higher grade (B → A)
- AJordan LakeAdams County · mi · Higher grade (B → A)
- BGoose LakeAdams County · mi · Higher overall water quality score
Nearby Lakes in Adams County
More Wisconsin Lake Rankings
State Parks Near Fawn Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Fawn Lake is a man-made reservoir impounded by the Fawn Lake (completed 1972), built primarily for recreation on the TROUT CREEK; earth-type dam, 19 ft tall and 1,000 ft long.
- Surface area
- 19 ac
- Normal storage
- 90 ac-ft
- Max storage
- 190 ac-ft
- Drainage area
- 2.2 sq mi
- Hazard class
- High
- Owner
- Adams County
Source: USACE National Inventory of Dams, NID ID WI00094 · Operator website
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2026-06-15
Monitoring stations: 2
Where to stay near Fawn Lake
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