Geneva Lake
Geneva Lake in Walworth County, Wisconsin has a water quality grade of A (Excellent). Water clarity: 21 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 135 ft. Surface area: 5401 acres.
Wisconsin DNR rates Smallmouth Bass as abundant on Geneva Lake. DNR survey details →
- Clarity
- 21 ft
- Max depth
- 135 ft
- Area
- 5,401 acres
- Type
- Oligotrophic
- Public access
- Yes
Next lake in Walworth County
Swipe left or right on this bar to open the next or previous lake.
Geneva Lake is a 5,401-acre cold, clear oligotrophic lake in Walworth County, Wisconsin with a maximum depth of 135 feet. Water quality is graded A based on 2 sampling years through 2026. The lake supports 6 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 3 public boat landings and 6 public beaches. Compared to the 18 other monitored lakes in Walworth County, Geneva Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-18. Grade methodology: LakeQuality methodology.
Watch Geneva Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Geneva Lake Water Quality Report Card (2026)
A printable one-page report card for Geneva Lake: grade, clarity, phosphorus, algae, multi-year trend, depth, and fish — with sources.
Swimming Safety
Grade onlyBacteria B
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.
Based on E. coli testing, Geneva Lake rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 4.1% of 579 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.
Water Quality Grade: A (Excellent)
Crystal clear, you can see 21 ft down. Phosphorus level: 13 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 21 ft | Not graded |
| Phosphorus | 13 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Geneva Lake
Compare lakeside cabins, hotels, and vacation rentals near Geneva Lake in Walworth 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 Geneva 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 trip? Cabins and lodging at Geneva Lake → · more Wisconsin lake trips
Current Conditions
USGS snapshot Jul 6, 2026, 5:00 AM from gauge 423525088260400 (Geneva Lake at Lake Geneva, WI). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Geneva Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (6,855 cells/mL) on November 17, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR rates Smallmouth Bass as abundant on Geneva Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Geneva Lake A from EPA Water Quality Portal chemistry. 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. 15 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 135 ft |
| Surface Area | 5,401 acres |
| Public Access | Yes |
Recreation & Access
- Linn RoadPublic
- Dandelion RoadPublic
- Williams BayPublic
- Chapin RoadPublic
- Schofield RoadPublic
- Abbey Springs Yacht ClubSemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Geneva 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.
Source: USGS Nonindigenous Aquatic Species (NAS) Database. Hover a chip to see scientific name, ecological context, status, and first-observed year.
County Ranking
Ranked #3 of 19 lakes in Walworth County
Nearby Lakes in Walworth County
Frequently asked questions about Geneva Lake
Where is Geneva Lake?
- Geneva Lake is a lake in Walworth County, Wisconsin. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Geneva Lake?
- Geneva Lake in Walworth County, Wisconsin has a water quality grade of A (Excellent). Water clarity: 21 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 135 ft. Surface area: 5401 acres.
Is Geneva Lake safe to swim in?
- Based on E. coli testing, Geneva Lake rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 4.1% of 579 samples across 9 seasons. That works out to a bacteria swim-safety grade of B — a historical summary of past testing, not a current reading. Geneva Lake has a water quality grade of A (Excellent). Bacteria levels can spike quickly after heavy rain, so always check Wisconsin's current beach and health-department advisories before you swim.
How deep is Geneva Lake?
- Geneva Lake has a maximum depth of 135 feet. The lake covers 5401 acres.
What fish are in Geneva Lake?
- Fish species found in Geneva Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Trout, Walleye. Geneva Lake is located in Walworth County, Wisconsin.
What did the DNR fisheries survey find at Geneva Lake?
- Wisconsin DNR rates Smallmouth Bass as abundant on Geneva Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Geneva Lake A from EPA Water Quality Portal chemistry. Catch rate is not a swim clearance and is not a weekly bite report.
What is the water level at Geneva Lake?
- The USGS snapshot on this page for Geneva Lake is 864.13 ft of water-surface elevation, recorded Jul 6, 2026, 5:00 AM at gauge 423525088260400. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Does Geneva Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Geneva Lake (clouds, ice, or an off-season gap). The most recent reading was low (6,855 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Geneva Lake?
- Geneva Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Linn Road, Dandelion Road, Williams Bay, Chapin Road, among others. Public access is listed as yes.
Explore Geneva Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Walworth County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Low nutrients, clear water, excellent for swimming
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Geneva Lake
Other Grade A Lakes in Wisconsin
Oligotrophic Lakes in Wisconsin
Compare Geneva Lake With Nearby Lakes
Where this data comes from
333 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_WQX197 samples · 2020–2026 - USGS Wisconsin Water Science Center
USGS-WI136 samples · 2020–2023
Analytical methods
- Phosphorus by Colorimetry
- Turbidity in Water
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
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