Red Cedar Lake
Jefferson County, Wisconsin344 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Red Cedar Lake. Here is what has been measured.
- Eutrophic
- Purple Loosestrife
- 6 ft max depth
- Public access
Red Cedar Lake in Jefferson County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 23.4 µg/L. Maximum depth: 6 ft. Surface area: 344 acres.
Wisconsin DNR lists Panfish as present on Red Cedar Lake. DNR survey details →
Red Cedar Lake is a 344-acre productive, nutrient-rich eutrophic lake in Jefferson County, Wisconsin with a maximum depth of 6 feet. Water clarity is declining over recent sampling years. The lake supports 1 documented fish species including Panfish. Public access is available. Compared to the 6 other monitored lakes in Jefferson County, Red Cedar Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-13. Methodology: how these readings are compared.
Red Cedar Lake covers about 340 acres in Jefferson County. If you are planning to stay, you can search lake houses and cabins around Red Cedar Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Red Cedar 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 Red Cedar Lake
These are the measurements Wisconsin DNR publishes for Red Cedar 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 4 ft. Phosphorus 23.4 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 23.4µg/L | Good GoodFairPoor |
| 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. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Red Cedar Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Red Cedar Lake typically sits around 69°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 79°F) and coldest in Sep (about 69°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (69°F) to its warmest (79°F).
Typical surface water temperature by month, from 24 field readings (2024–2025) via the EPA Water Quality Portal. See the full Red Cedar Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Red Cedar Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (41,305 cells/mL) on April 25, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR lists Panfish as present on Red Cedar Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Red Cedar Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. 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. Monitored by volunteers since 2004. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
6 ft
Surface area
344 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.1 mi
HydroLAKES / HydroSHEDS
Elevation
837 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Red Cedar Lake
Compare lakeside cabins, hotels, and vacation rentals near Red Cedar Lake in Jefferson 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 Red Cedar 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 Red Cedar Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fish Species
Click a species to see every lake where it is documented.
Fishing Red Cedar 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.
Water Quality Trend: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening6 years
Phosphorus
Improving-0.52 µg/L/yr7 years
Nearby Lakes in Jefferson County
Frequently asked questions about Red Cedar Lake
Where is Red Cedar Lake?
- Red Cedar Lake is a lake in Jefferson County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Red Cedar Lake?
- Red Cedar Lake in Jefferson County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 23.4 µg/L. Maximum depth: 6 ft. Surface area: 344 acres.
Is Red Cedar Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Red Cedar Lake?
- Red Cedar Lake typically sits around 69°F at the surface in September, from 24 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Red Cedar Lake?
- Red Cedar Lake has a maximum depth of 6 feet. The lake covers 344 acres.
What fish are in Red Cedar Lake?
- Fish species found in Red Cedar Lake include Panfish. Red Cedar Lake is located in Jefferson County, Wisconsin.
What did the DNR fisheries survey find at Red Cedar Lake?
- Wisconsin DNR lists Panfish as present on Red Cedar Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Red Cedar Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Does Red Cedar Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Red Cedar Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (41,305 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Can I fish at Red Cedar Lake?
- Public access to Red Cedar 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 Red Cedar Lake across LakeQuality
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Jefferson 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
State Parks Near Red Cedar Lake
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
38 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX38 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes