Nelson Lake
Sawyer County, Wisconsin2,503 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Nelson Lake. Here is what has been measured.
- Eutrophic
- 76 ft max depth
- Public access
Nelson Lake in Sawyer County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 22.8 µg/L. Surface area: 2503 acres.
Nelson Lake is a 2,503-acre productive, nutrient-rich eutrophic lake in Sawyer County, Wisconsin with an estimated average depth of about 76 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 3 public boat landings. Compared to the 44 other monitored lakes in Sawyer County, Nelson Lake ranks #18 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-15. Methodology: how these readings are compared.
Nelson Lake covers about 2,500 acres in Sawyer County. It has 3 public boat landings, so a lakefront rental is not the only way to get a boat on the water. Vrbo is where to look for cabins and lake homes around Nelson Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Nelson Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch3 documented ramps
- Camping2 public campgrounds nearby
- Big water2,503 acres
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 Nelson 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 Nelson Lake
These are the measurements Wisconsin DNR publishes for Nelson 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 5 ft. Phosphorus 22.8 µg/L. TSI 52.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 22.8µg/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. | 52 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Nelson Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Nelson Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (432,514 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Nelson Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2023Nelson Lake spring shocking and netting survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
Lake Details
Max depth
~76 ft est.
Surface area
2,503 acres
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 Nelson Lake.
Lake Size & Watershed
Watershed (drainage) area
53 sq mi
HydroLAKES / HydroSHEDS
Shoreline
25 mi
HydroLAKES / HydroSHEDS
Elevation
1,250 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.
Recreation & Access
- GerlachsPublic
- Totagatic RiverPublic
- Nelson Lake ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Nelson Lake
- Phipps Landing4.0 km
- Phipps4.2 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Nelson Lake
Compare lakeside cabins, hotels, and vacation rentals near Nelson 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 Nelson Lake
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Planning a trip? Cabins and lodging at Nelson Lake → · more Wisconsin lake trips
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Fishing Nelson Lake
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Reservoir Info (USACE NID)
Nelson Lake is a man-made reservoir impounded by the Totagatic (completed 1936), built primarily for recreation on the TOTAGATIC; gravity-type dam, 20 ft tall and 556 ft long.
- Surface area
- 2,503 ac
- Normal storage
- 21,000 ac-ft
- Max storage
- 38,000 ac-ft
- Drainage area
- 49.8 sq mi
- Hazard class
- Low
- Owner
- Sawyer County
Source: USACE National Inventory of Dams, NID ID WI00197 · Operator website
Nearby Lakes in Sawyer County
Frequently asked questions about Nelson Lake
Where is Nelson Lake?
- Nelson Lake is a lake in Sawyer County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Nelson Lake?
- Nelson Lake in Sawyer County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 22.8 µg/L. Surface area: 2503 acres.
Is Nelson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Nelson Lake?
- No published bathymetric survey covers Nelson Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 76 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 2503 acres.
Does Nelson Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Nelson Lake (clouds, ice, or an off-season gap). The most recent reading was high (432,514 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Nelson Lake?
- Nelson Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Gerlachs, Totagatic River, Nelson Lake Park. Public access is listed as yes.
Can I fish at Nelson Lake?
- Nelson Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. 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.
Are there campgrounds on Nelson Lake?
- Nelson Lake has 2 public campgrounds from USGS The National Map within 5 km, including Phipps Landing, Phipps. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Nelson Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Sawyer County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Hayward Lakes area
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the Chippewa River Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
More lakes in Wisconsin
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Compare Nelson Lake With Nearby Lakes
Where this data comes from
186 measurements from 3 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX186 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (3)
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)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles