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LakeQuality

Yellowstone Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #2 of 2 lakes in the county · 1.3 ft clear · Hypereutrophic · 453 acres · from F
Hypereutrophic

Yellowstone Lake in Lafayette County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 1.3 ft visibility. Phosphorus: 156 µg/L. Maximum depth: 14 ft. Surface area: 453 acres.

Clarity
1.3 ft
Typical in August
79°F
Max depth
14 ft
Area
453 acres
Type
Hypereutrophic
Trend
Improving
Public access
Yes

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Yellowstone Lake

Next lake in Lafayette County

DHidden Valley Lake5.2 ft clear · Lafayette CountyView →
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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. Water quality is graded D based on 1 sampling years through 2026. 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. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Bacteria C

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.

C
Bacteria swim-safety grade: C
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.

Compare the safest swimming lakes near Madison

Get alerts for Yellowstone Lake

Water Quality Grade: D (Nutrient-rich)

Very murky, less than 1.3 ft of visibility. Phosphorus level: 156 µg/L. Trophic State Index: 75.

MetricValueGrade
Water Clarity (Secchi Depth)1.3 ftNot graded
Phosphorus156 µg/LPoor
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)75Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Yellowstone Lake are listed below.

Top-rated places to stay near Yellowstone Lake

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 →

Water Temperature

Yellowstone Lake typically sits around 79°F at the surface in August. 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
Mar
46°
Apr
May
Jun
Jul
78°
Aug
79°
Sep
68°
Oct
Nov
Dec

Typical surface water temperature by month, from 27 field readings (20242026) via the EPA Water Quality Portal. See the full Yellowstone Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth14 ft
Surface Area453 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
41 sq mi
Shoreline
4.9 mi
Elevation
833 ft

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

Recreation & Access

2
Boat Landings
Yes
Public Access
  • Yellowstone Lake State Park - SouthPublic
  • Yellowstone Lake State Park - NorthPublic

Fish Species

Click a species to see every graded 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

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)

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).

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.089 m/yr5
Phosphorus Improving-13.5 µg/L/yr5
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)

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.

County Ranking

Ranked #2 of 2 lakes in Lafayette County

Nearby Lakes With Higher Grades

Yellowstone Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.

See full comparison →

Nearby Lakes in Lafayette County

Frequently asked questions about Yellowstone Lake

What is the water quality grade for Yellowstone Lake?

Yellowstone Lake in Lafayette County, Wisconsin has a water quality grade of D (Nutrient-rich). 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 works out to a bacteria swim-safety grade of C — a historical summary of past testing, not a current reading. Yellowstone Lake has a water quality grade of D (Nutrient-rich). Bacteria levels can spike quickly after heavy rain, so always check Wisconsin's current beach and health-department advisories before you swim.

What is the water temperature of Yellowstone Lake?

Yellowstone Lake typically sits around 79°F at the surface in August, 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.

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.

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)

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

Impairment status from EPA ATTAINS 303(d) database

Regulated discharger data from EPA ECHO (ICIS-NPDES)

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