Mud Lake
Mud Lake in Sawyer County, Wisconsin has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 18.5 µg/L. Maximum depth: 15 ft. Surface area: 464 acres.
Wisconsin DNR rates Largemouth Bass as abundant on Mud Lake. DNR survey details →
- Clarity
- 10 ft
- Max depth
- 15 ft
- Area
- 464 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Mud Lake is a 464-acre mesotrophic lake in Sawyer County, Wisconsin with a maximum depth of 15 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 4 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 44 other monitored lakes in Sawyer County, Mud Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-25. Grade methodology: LakeQuality 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)
Good clarity, visible to about 10 ft. Phosphorus level: 18.5 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 18.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mud Lake
Compare lakeside cabins, hotels, and vacation rentals near Mud Lake in Sawyer 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 Mud Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Mud Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (9,036 cells/mL) on June 20, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR rates Largemouth Bass as abundant on Mud Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mud Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 4 years of monitoring is improving. 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 2020. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 15 ft |
| Surface Area | 464 acres |
| Public Access | Yes |
Recreation & Access
- Chief RiverPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mud 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: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.1 m/yr | 3 |
| Phosphorus | ↑ Improving | -1.37 µg/L/yr | 4 |
County Ranking
Ranked #19 of 45 lakes in Sawyer County
Nearby Lakes With Higher Grades
Mud Lake holds Grade B. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Sawyer County
Frequently asked questions about Mud Lake
Where is Mud Lake?
- Mud Lake is a lake in Sawyer County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Mud Lake?
- Mud Lake in Sawyer County, Wisconsin has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 18.5 µg/L. Maximum depth: 15 ft. Surface area: 464 acres.
Is Mud Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Mud Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Mud Lake?
- Mud Lake has a maximum depth of 15 feet. The lake covers 464 acres.
What fish are in Mud Lake?
- Fish species found in Mud Lake include Musky, Panfish, Largemouth Bass, Walleye. Mud Lake is located in Sawyer County, Wisconsin.
What did the DNR fisheries survey find at Mud Lake?
- Wisconsin DNR rates Largemouth Bass as abundant on Mud Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mud Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 4 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Does Mud Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Mud Lake (clouds, ice, or an off-season gap). The most recent reading was low (9,036 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Mud Lake?
- Mud Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Chief River. Public access is listed as yes.
Explore Mud Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Sawyer County
Species activity outlook by water temperature and season
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Where to stay at Wisconsin's top lakes, each with its grade
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Moderate nutrients, good water quality
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Where this data comes from
29 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_WQX29 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