Lake Keesus
Waukesha County, Wisconsin235 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Lake Keesus. Here is what has been measured.
- Mesotrophic
- 2 aquatic invasives
- 42 ft max depth
- Public access
Lake Keesus in Waukesha County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 15.8 µg/L. Maximum depth: 42 ft. Surface area: 235 acres.
Wisconsin DNR rates Largemouth Bass as abundant on Lake Keesus. DNR survey details →
Lake Keesus is a 235-acre mesotrophic lake in Waukesha County, Wisconsin with a maximum depth of 42 feet. Overall water quality is improving over recent sampling years. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 1 public boat landing. Compared to the 34 other monitored lakes in Waukesha County, Lake Keesus ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-14. Methodology: how these readings are compared.
Lake Keesus covers about 240 acres in Waukesha County. It has one public boat landing. If you are planning to stay, you can search lake houses and cabins around Lake Keesus on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Lake Keesus is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing4 species recorded
- Deep water42 ft surveyed max depth
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 Lake Keesus 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 Keesus
These are the measurements Wisconsin DNR publishes for Lake Keesus, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9.2 ft. Phosphorus 15.8 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 15.8µg/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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Lake Keesus
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR rates Largemouth Bass as abundant on Lake Keesus.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake Keesus’s water-quality measurements separately, and the water-quality trend over 6 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. 3 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Lake Keesus 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).
- 2023Lake Keesus spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
Lake Details
Max depth
42 ft
Surface area
235 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Shoreline
4.1 mi
HydroLAKES / HydroSHEDS
Elevation
958 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake KeesusPublic
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 Keesus
Compare lakeside cabins, hotels, and vacation rentals near Lake Keesus in Waukesha 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 Lake Keesus
Prices for Oct 16–18, 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 Lake Keesus’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Lake Keesus
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 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Improving-1.06 µg/L/yr6 years
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Keesus under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Essential Industries IncMerton · 1.4 mi away · NPDES WI0066648Recent violation
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 Waukesha County
Frequently asked questions about Lake Keesus
Where is Lake Keesus?
- Lake Keesus is a lake in Waukesha 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 Keesus?
- Lake Keesus in Waukesha County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 15.8 µg/L. Maximum depth: 42 ft. Surface area: 235 acres.
Is Lake Keesus safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Keesus?
- Lake Keesus has a maximum depth of 42 feet. The lake covers 235 acres.
What fish are in Lake Keesus?
- Fish species found in Lake Keesus include Panfish, Largemouth Bass, Northern Pike, Walleye. Lake Keesus is located in Waukesha County, Wisconsin.
What did the DNR fisheries survey find at Lake Keesus?
- Wisconsin DNR rates Largemouth Bass as abundant on Lake Keesus. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake Keesus’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Lake Keesus?
- Lake Keesus has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Keesus. Public access is listed as yes.
Can I fish at Lake Keesus?
- Lake Keesus has 1 documented boat landing 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 Keesus 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 Waukesha County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its readings
Wisconsin's cleanest lakes, ranked on agency measurements
More lakes in Wisconsin
State Parks Near Lake Keesus
Other Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
48 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_WQX48 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
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)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory