Grignon Lake
Oconto County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Grignon Lake. Here is what has been measured.
- 31 ft max depth
- Public access
- Limited data
Grignon Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 22.9 µg/L.
Grignon Lake is a lake in Oconto County, Wisconsin with an estimated average depth of about 31 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2021-07-28. Methodology: how these readings are compared.
For a place on the water, look through cabin and lake-house rentals near Grignon Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grignon Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Grignon Lake
These are the measurements Wisconsin DNR publishes for Grignon Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6 ft. Phosphorus 22.9 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 22.9µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Grignon Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~31 ft est.
Public access
Yes
Listed by Wisconsin DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Grignon Lake.
Lake Size & Watershed
Watershed (drainage) area
25 sq mi
HydroLAKES / HydroSHEDS
Surface area
30 acres
HydroLAKES / HydroSHEDS
Shoreline
0.9 mi
HydroLAKES / HydroSHEDS
Elevation
840 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Grignon Lake
Compare lakeside cabins, hotels, and vacation rentals near Grignon Lake in Oconto 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 Grignon Lake
Prices for Oct 16–18, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Grignon Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Grignon Lake
Water quality readings over time
2 seasons of samples on record (2020–2021). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Nearby Lakes in Oconto County
Frequently asked questions about Grignon Lake
Where is Grignon Lake?
- Grignon Lake is a lake in Oconto County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Grignon Lake?
- Grignon Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 22.9 µg/L.
Is Grignon Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Grignon Lake?
- No published bathymetric survey covers Grignon Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 31 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Can I fish at Grignon Lake?
- Public access to Grignon Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Grignon Lake across LakeQuality
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Oconto County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its readings
Wisconsin's cleanest lakes, ranked on agency measurements
More lakes in Wisconsin
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
11 measurements from 2 monitoring stations, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX11 samples · 2020–2021
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)