Where is Yellowstone Lake?

Yellowstone Lake is a lake in Lafayette County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.

Is Yellowstone Lake safe to swim in?

Based on E. coli testing, Yellowstone Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 6.1% of 114 samples across 9 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Yellowstone Lake is safe to swim in today is a call for Wisconsin's water agency and the county health department; check their current beach advisories before you swim.

What is the water temperature of Yellowstone Lake?

Yellowstone Lake typically sits around 68°F at the surface in September, from 27 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.

How deep is Yellowstone Lake?

Yellowstone Lake has a maximum depth of 14 feet. The lake covers 453 acres.

Are there boat ramps on Yellowstone Lake?

Yellowstone Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Yellowstone Lake State Park - South, Yellowstone Lake State Park - North. Public access is listed as yes.

Can I fish at Yellowstone Lake?

Yellowstone Lake 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.

Yellowstone Lake

Lafayette County, Wisconsin453 acresView map Directions

Wisconsin DNR publishes the water-quality measurements for Yellowstone Lake. Here is what has been measured.

Clarity

1.3 ft

Murkier than most

Secchi · sampled 2026

Phosphorus

156 µg/L

More phosphorus than most

Measured by Wisconsin DNR

Water temp

~68°F

Typical for Sep · EPA WQP

Max depth

14 ft

Bathymetric survey

Area

453 acres

Surface area

Type

Hypereutrophic

Trophic class

Hypereutrophic
Impaired · Nutrients (phosphorus, nitrogen)
3 aquatic invasives
14 ft max depth
Public access

See the measurements Directions Where to stay

Yellowstone Lake in Lafayette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 156 µg/L. Maximum depth: 14 ft. Surface area: 453 acres.

Wisconsin DNR rates Panfish as abundant on Yellowstone Lake. DNR survey details →

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Yellowstone Lake is a 453-acre highly nutrient-loaded hypereutrophic lake in Lafayette County, Wisconsin with a maximum depth of 14 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Lafayette County, Yellowstone Lake ranks #2 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-03-31. Methodology: how these readings are compared.

Yellowstone Lake covers about 450 acres in Lafayette 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 Yellowstone Lake, and Booking.com and Expedia search hotels near the lake for your dates.

What Yellowstone Lake is good for

From access and monitoring records, not editorial picks.

Boat launch2 documented ramps
Fishing6 species recorded

Swimming conditions

Readings only

Recreation use not supported

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.

Bacteria testing record

from E. coli testing · 114 samples, 9 seasons

Based on E. coli testing, Yellowstone Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 6.1% of 114 samples across 9 seasons.

This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Wisconsin’s current beach and health-department advisories before swimming.

Whether Yellowstone 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.

Compare swimming lakes near Madison →

Get alerts for Yellowstone Lake →

Water quality measurements for Yellowstone Lake

These are the measurements Wisconsin DNR publishes for Yellowstone Lake, 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 1.3 ft of visibility. Phosphorus 156 µg/L. TSI 75.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	1.3ft	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	156µg/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.	75	Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic

Very high nutrients, dense algae, poor clarity

Ask about Yellowstone Lake

Answers come straight from the public measurements and survey records on this page.

Water Temperature

Yellowstone Lake typically sits around 68°F at the surface in September. Summer average is about 79°F. Usually warmest in Aug (about 79°F) and coldest in Mar (about 46°F). These are typical values by month — not a live reading.

Jan

Feb

46°

Mar

Apr

May

Jun

78°

Jul

79°

Aug

68°

Sep

Oct

Nov

Dec

Column height runs from this lake’s coldest month (46°F) to its warmest (79°F).

Typical surface water temperature by month, from 27 field readings (2024–2026) via the EPA Water Quality Portal. See the full Yellowstone Lake water temperature breakdown →

DNR fisheries survey

Wisconsin DNR rates Panfish as abundant on Yellowstone Lake.

A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Yellowstone Lake’s water-quality measurements separately, and the water-quality trend over 5 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. 2 stations on file (most recent sample 2025).

DNR Assessment

Poor · Reservoir lake

Trophic State Index 82 (hypereutrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Abundant)Musky(Common)Largemouth Bass(Common)Northern Pike(Present)Trout(Present)Walleye(Present)

Contour map (PDF) →Full WI DNR LakePage →Water quality stations →

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Yellowstone Lake covering fish populations, stocking, water quality, and management. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

2023
Yellowstone Lake rough fish removal assessment, 2023
Fisheries Survey · WI DNR · 2023 (PDF)
2018
Yellowstone Lake comprehensive survey 2018
Comprehensive Survey · WI DNR · 2018 (PDF)
2010
Yellowstone Lake muskellunge 2010
Musky Survey · WI DNR · 2010 (PDF)

Lake Details

Max depth

14 ft

Surface area

453 acres

Public access

Yes

Listed by Wisconsin DNR

Lake Size & Watershed

Watershed (drainage) area

41 sq mi

HydroLAKES / HydroSHEDS

Shoreline

4.9 mi

HydroLAKES / HydroSHEDS

Elevation

833 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

Boat Landings

Yes

Public Access

Yellowstone Lake State Park - SouthPublic
Yellowstone Lake State Park - NorthPublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Stays via Stay22

Stays near Yellowstone Lake

Compare lakeside cabins, hotels, and vacation rentals near Yellowstone Lake in Lafayette 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 Yellowstone Lake are listed below.

Top-rated places to stay near Yellowstone 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 Yellowstone Lake’s readings

Email me when new measurements post for this lake. Updates stay free.

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Fish Species

Musky Panfish Largemouth Bass Northern Pike Trout Walleye

Click a species to see every lake where it is documented.

Fishing Yellowstone 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.

Curly-Leaf PondweedPurple LoosestrifeRusty Crayfish

Water Quality Trend: Improving

Based on 5 years of monitoring (2021–2025).

Water clarity
Improving
5 years
Phosphorus
Improving
-13.5 µg/L/yr5 years

See year-by-year chart →

Reservoir Info (USACE NID)

Yellowstone Lake is a man-made reservoir impounded by the Yellowstone (completed 1953), built primarily for recreation; gravity-type dam, 32 ft tall and 1,370 ft long.

Surface area: 455 ac
Normal storage: 2,730 ac-ft
Max storage: 6,400 ac-ft
Drainage area: 41.7 sq mi
Hazard class: High
Owner: Wisconsin Department of Natural Resources

Source: USACE National Inventory of Dams, NID ID WI00071 · Operator website

EPA Impairment Status

Yellowstone Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Nutrients (phosphorus, nitrogen)

Designated uses not supporting: Aquatic life, Recreation.

Source: EPA ATTAINS assessment unit WI10009851 · Official waterbody report

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Yellowstone Lake under Clean Water Act (NPDES) discharge permits.

Wi Dnr Yellowstone Lake State Park Wwtf
Fayette · 0.8 mi away · NPDES WI0031879

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 Lafayette County

Hidden Valley Lake5.2 ft clear · Eutrophic—View →Ludden Lake1.5 ft clear · Hypereutrophic—View →Cox Hollow Lake—View →Twin Valley Lake—View →Helen Lake3.4 ft clear · Eutrophic—View →Black Hawk Lake5 ft clear · Eutrophic—View →

Frequently asked questions about Yellowstone Lake

Where is Yellowstone Lake?: Yellowstone Lake is a lake in Lafayette County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Yellowstone Lake?: Yellowstone Lake in Lafayette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 156 µg/L. Maximum depth: 14 ft. Surface area: 453 acres.
Is Yellowstone Lake safe to swim in?: Based on E. coli testing, Yellowstone Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 6.1% of 114 samples across 9 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Yellowstone Lake is safe to swim in today is a call for Wisconsin's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Yellowstone Lake?: Yellowstone Lake typically sits around 68°F at the surface in September, from 27 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Yellowstone Lake?: Yellowstone Lake has a maximum depth of 14 feet. The lake covers 453 acres.
What fish are in Yellowstone Lake?: Fish species found in Yellowstone Lake include Musky, Panfish, Largemouth Bass, Northern Pike, Trout, Walleye. Yellowstone Lake is located in Lafayette County, Wisconsin.
What did the DNR fisheries survey find at Yellowstone Lake?: Wisconsin DNR rates Panfish as abundant on Yellowstone Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Yellowstone Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Yellowstone Lake?: Yellowstone Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Yellowstone Lake State Park - South, Yellowstone Lake State Park - North. Public access is listed as yes.
Can I fish at Yellowstone Lake?: Yellowstone Lake 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 Yellowstone Lake across LakeQuality

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State Parks Near Yellowstone Lake

Yellowstone Lake State Park

State Park · 0.5 mi

New Glarus Woods State Park

State Park · 17.2 mi

Belmont Mound State Park

State Park · 19.3 mi

Blue Mound State Park

State Park · 19.3 mi

Other Lakes in Wisconsin

Ludden Lake

Iowa County · 1.5 ft

Helen Lake

Iowa County · 3.4 ft

Hill Slough Lake

Sauk County · 4.4 ft

Investment Court Pond

Dane County · Measured

Cathedral Point Pond

Dane County · Measured

Whalen Road Pond

Dane County · Measured

Hypereutrophic Lakes in Wisconsin

Ludden Lake Investment Court Pond Cathedral Point Pond Hawthorne Hills South Pond

Where this data comes from

58 measurements from 3 monitoring stations, 2021–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

Wisconsin Department of Natural ResourcesWIDNR_WQX58 samples · 2021–2026

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.