Lily Lake
Forest County, WisconsinLimited DataMesotrophic
On the LakeGrade scale Lily Lake grades a B, with clarity at 11.0 ft and phosphorus readings still being added placing it above the Wisconsin median.
Mesotrophic conditions dominate at Lily Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 24 ft puts Lily Lake in the middle of Wisconsin's depth distribution. At 217 acres, Lily Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Lily Lake sits at rank 18 of 34 in Forest County, in the lower half of the local distribution.
An invasive species record — Banded Mystery Snail — has been logged at Lily Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye among the lake's 5 documented species — a notable draw for Wisconsin anglers. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 11 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 217 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Lily Lake (14-day solunar calendar)
→ Is it safe to eat fish from Lily Lake? (mercury & PFAS guide)
→ Lily Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.143 m/yr | 6 |
Location
County Ranking
Ranked #18 of 34 lakes in Forest County
Cleaner Lakes Within 30 Miles
Lily Lake holds Grade B. 3 nearby lakes hold higher grades.
Nearby Lakes in Forest County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2009. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Lily Lake covering fish populations, stocking, water quality, and management. 1 report on file.
- 2022Lily Lake fisheries summary, 2022Fisheries Survey · WI DNR · 2022 (PDF)
Reservoir Info (USACE NID)
Lily Lake is a man-made reservoir impounded by the Lily Lake (completed 1976), built primarily for recreation on the LILY RIVER; earth-type dam, 7 ft tall.
- Surface area
- 213 ac
- Normal storage
- 600 ac-ft
- Max storage
- 1,000 ac-ft
- Drainage area
- 18 sq mi
- Hazard class
- Low
- Owner
- Town Of Nashville
Source: USACE National Inventory of Dams, NID ID WI12668 · Operator website
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-20
Monitoring stations: 1