Mercer Lake
Mercer Lake in Oneida County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 23 ft. Surface area: 255 acres.
Wisconsin DNR lists Musky as common on Mercer Lake. DNR survey details →
- Max depth
- 23 ft
- Area
- 255 acres
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Why Mercer Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Mercer Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Mercer Lake is a 255-acre lake in Oneida County, Wisconsin with a maximum depth of 23 feet. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-11-16. Grade methodology: LakeQuality methodology.
Watch Mercer Lake water quality
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Mercer Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples |
Where to stay near Mercer Lake
Compare lakeside cabins, hotels, and vacation rentals near Mercer Lake in Oneida County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Mercer Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Wisconsin DNR lists Musky as common on Mercer Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Mercer Lake — official chemistry is on file, not a letter. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 23 ft |
| Surface Area | 255 acres |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mercer Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Graded lakes near Mercer Lake
Mercer Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Oneida County
Frequently asked questions about Mercer Lake
Where is Mercer Lake?
- Mercer Lake is a lake in Oneida County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Mercer Lake?
- Mercer Lake in Oneida County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 23 ft. Surface area: 255 acres.
Is Mercer Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Mercer Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Mercer Lake?
- Mercer Lake has a maximum depth of 23 feet. The lake covers 255 acres.
What fish are in Mercer Lake?
- Fish species found in Mercer Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Mercer Lake is located in Oneida County, Wisconsin.
What did the DNR fisheries survey find at Mercer Lake?
- Wisconsin DNR lists Musky as common on Mercer Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Mercer Lake — official chemistry is on file, not a letter. Catch rate is not a swim clearance and is not a weekly bite report.
Explore Mercer Lake across LakeQuality
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Where this data comes from
2 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX2 samples · 2025
Analytical methods
- Total Phosphorus After Block Digestion
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes