Bishop Lake
Forest County, WisconsinMesotrophic
On the LakeGrade scale Bishop Lake grades a B, with clarity at 7.0 ft and 25 µg/L of phosphorus placing it above the Wisconsin median. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.
A TSI near 50 places Bishop Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. At only 12 ft deep, Bishop Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. At 288 acres, Bishop Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within the 34 graded lakes of Forest County, Bishop Lake sits at rank 28, near the bottom of the county list.
An invasive species record — Banded Mystery Snail — has been logged at Bishop Lake; Wisconsin DNR maintains the official infested-waters list. The fishery is bass-led, with 3 documented species across the lake's records. 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 2025-09-17. Grade methodology: LakeGrade methodology.
Track Bishop Lake
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 7 ft. Phosphorus level: 25 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | C |
| Phosphorus | 25 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 12 ft |
| Surface Area | 288 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Bishop Lake (14-day solunar calendar)
→ Is it safe to eat fish from Bishop Lake? (mercury & PFAS guide)
→ Bishop 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: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.25 m/yr | 2 |
| Phosphorus | → Stable | -0.2 µg/L/yr | 4 |
Location
County Ranking
Ranked #28 of 34 lakes in Forest County
Cleaner Lakes Within 30 Miles
Bishop Lake holds Grade B. 3 nearby lakes hold higher grades.
- ALake MetongaForest County · mi · Higher grade (B → A)
- BMole LakeForest County · mi · Higher overall water quality score
- BLittle Sand LakeForest County · mi · Higher overall water quality score
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 1995. 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 Bishop Lake covering fish populations, stocking, water quality, and management. 1 report on file.
- 2024Bishop Lake spring netting and shocking survey, 2024Netting Survey · WI DNR · 2024 (PDF)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-17
Monitoring stations: 2