Lake Redstone
Sauk County, Wisconsin612 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Lake Redstone. Here is what has been measured.
- Eutrophic
- 35 ft max depth
- Public access
Lake Redstone in Sauk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 89 µg/L. Surface area: 612 acres.
Lake Redstone is a 612-acre productive, nutrient-rich eutrophic lake in Sauk County, Wisconsin with an estimated average depth of about 35 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 6 other monitored lakes in Sauk County, Lake Redstone ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-18. Methodology: how these readings are compared.
Lake Redstone covers about 610 acres in Sauk County. It has 2 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 Lake Redstone, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Redstone is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming conditions
Readings onlyElevated nutrients
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 Lake Redstone 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 Lake Redstone
These are the measurements Wisconsin DNR publishes for Lake Redstone, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. Phosphorus 89 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 89µg/L | Poor 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. | 68 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Redstone
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~35 ft est.
Surface area
612 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 Lake Redstone.
Lake Size & Watershed
Watershed (drainage) area
27 sq mi
HydroLAKES / HydroSHEDS
Shoreline
10.6 mi
HydroLAKES / HydroSHEDS
Elevation
919 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
- Redstone Fox CourtPublic
- Lavalle RoadPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lake Redstone
Compare lakeside cabins, hotels, and vacation rentals near Lake Redstone in Sauk 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Lake Redstone are listed below.
Top-rated places to stay near Lake Redstone
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 trip? Cabins and lodging at Lake Redstone → · more Wisconsin lake trips
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Fishing Lake Redstone
Water Quality Trend: Worsening
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening6 years
Phosphorus
Worsening+7.12 µg/L/yr7 years
Reservoir Info (USACE NID)
Lake Redstone is a man-made reservoir impounded by the Lake Redstone (completed 1967), built primarily for recreation on the Big Creek; gravity-type dam, 50 ft tall and 600 ft long.
- Surface area
- 612 ac
- Normal storage
- 8,700 ac-ft
- Max storage
- 15,200 ac-ft
- Drainage area
- 29.9 sq mi
- Hazard class
- High
- Owner
- Sauk County
Source: USACE National Inventory of Dams, NID ID WI00707 · Operator website
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Lake Redstone under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- La Valle Wastewater Treatment FacilityLa Valle · 2.7 mi away · NPDES WI0028878Recent violation
- Kinnamon Ridge Dairy LlcIronton, Town Of · 4.9 mi away · NPDES WI0065129
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Sauk County
Frequently asked questions about Lake Redstone
Where is Lake Redstone?
- Lake Redstone is a lake in Sauk County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Lake Redstone?
- Lake Redstone in Sauk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 89 µg/L. Surface area: 612 acres.
Is Lake Redstone safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Redstone?
- No published bathymetric survey covers Lake Redstone, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 35 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 612 acres.
Are there boat ramps on Lake Redstone?
- Lake Redstone has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Redstone Fox Court, Lavalle Road. Public access is listed as yes.
Can I fish at Lake Redstone?
- Lake Redstone has 2 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.
Explore Lake Redstone across LakeQuality
Depth, room, public access, and the state wake-sport rules
7.4 mi away · cable-pulled, no boat wake
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Fish species and best lakes in Sauk County
Species activity outlook by water temperature and season
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Where to stay at Wisconsin's top lakes, each with its readings
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Where this data comes from
306 measurements from 6 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_WQX306 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (6)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory