Red Cedar Lake
Red Cedar Lake in Jefferson County, Wisconsin has a water quality grade of B (Good). Water clarity: 4 ft visibility. Phosphorus: 23.4 µg/L. Maximum depth: 6 ft. Surface area: 344 acres.
- Clarity
- 4 ft
- Typical in August
- 74°F
- Max depth
- 6 ft
- Area
- 344 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Jefferson County
Red Cedar Lake is a 344-acre productive, nutrient-rich eutrophic lake in Jefferson County, Wisconsin with a maximum depth of 6 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is declining over recent sampling years. The lake supports 1 documented fish species including Panfish. Public access is available with 1 public boat landing. 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Murky, only visible to about 4 ft. Phosphorus level: 23.4 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | Not graded |
| Phosphorus | 23.4 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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
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Water Temperature
Red Cedar Lake typically sits around 74°F at the surface in August. 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.
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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 6 ft |
| Surface Area | 344 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Red Cedar LakePublic
Fish Species
Click a species to see every graded 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.
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)
Water Quality Trend: → Stable
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.101 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.52 µg/L/yr | 7 |
County Ranking
Ranked #2 of 7 lakes in Jefferson County
Nearby Lakes in Jefferson County
Frequently asked questions about Red Cedar Lake
What is the water quality grade for Red Cedar Lake?
- Red Cedar Lake in Jefferson County, Wisconsin has a water quality grade of B (Good). 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?
- Good for swimming, clear water with low algae levels. Red Cedar Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Red Cedar Lake?
- Red Cedar Lake typically sits around 74°F at the surface in August, 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.
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.
Are there boat ramps on Red Cedar Lake?
- Red Cedar Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Red Cedar Lake. Public access is listed as yes.
Explore Red Cedar Lake across LakeGrade
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High nutrients, frequent algae, reduced clarity
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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)
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
Named boat-access points from the USGS National Boat Ramps inventory