Sealion Lake
Florence County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Sealion Lake. Here is what has been measured.
- Limited data
Sealion Lake in Florence County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 25.6 ft visibility.
Sealion Lake is a lake in Florence County, Wisconsin. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-07-08. Methodology: how these readings are compared.
What Sealion Lake is good for
From access and monitoring records, not editorial picks.
- Clear water25.6 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Sealion 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 Sealion Lake
These are the measurements Wisconsin DNR publishes for Sealion Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 25.6 ft down. TSI 30.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 25.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading 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. | 30 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Sealion Lake
Answers come straight from the public measurements and survey records on this page.
Stays via Stay22
Stays near Sealion Lake
Compare lakeside cabins, hotels, and vacation rentals near Sealion Lake in Florence 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 Sealion Lake
Prices for Oct 9–11, 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 Sealion Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Sealion Lake
Water Quality Trend: Worsening
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening7 years
Phosphorus
Worsening+3 µg/L/yr3 years
Nearby Lakes in Florence County
Frequently asked questions about Sealion Lake
Where is Sealion Lake?
- Sealion Lake is a lake in Florence County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Sealion Lake?
- Sealion Lake in Florence County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 25.6 ft visibility.
Is Sealion Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Sealion Lake across LakeQuality
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Florence 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
Oligotrophic Lakes in Wisconsin
Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX1 sample · 2022
Monitoring station identifiers (1)
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.