North Bay Lake
Vilas County, WisconsinLimited DataMesotrophic
North Bay Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
Mesotrophic conditions dominate at North Bay Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 19 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. North Bay Lake covers 270 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. North Bay Lake ranks 179 of 202 in Vilas County — at the lower end of the locally monitored distribution.
Eurasian watermilfoil has been documented at North Bay Lake, requiring shoreline management to keep dense mats from crowding native vegetation. The fishery includes walleye alongside the lake's other 5 documented species — a notable draw for Wisconsin anglers. A documented public access point at North Bay Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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 2022-10-05. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 13.1 ft. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.1 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 19 ft |
| Surface Area | 270 acres |
| Public Access | Yes |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for North Bay Lake (14-day solunar calendar)
→ Is it safe to eat fish from North Bay Lake? (mercury & PFAS guide)
→ North Bay Lake fishing regulations (limits, seasons, special rules)
Invasive Species
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.188 m/yr | 7 |
| Phosphorus | ↑ Improving | -1.13 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #179 of 202 lakes in Vilas County
Cleaner Lakes Within 30 Miles
North Bay Lake holds Grade B. 2 nearby lakes hold higher grades.
- ASnipe LakeVilas County · 1.2 mi · Higher grade (B → A)
- APickerel LakeVilas County · 1.2 mi · Higher grade (B → A)
Nearby Lakes in Vilas 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 1991. 10 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2022-10-05
Monitoring stations: 1