Mcginnis Lake
Mcginnis Lake in Adams County, Wisconsin has a water quality grade of B (Good). Water clarity: 7 ft visibility. Phosphorus: 20.8 µg/L. Maximum depth: 28 ft. Surface area: 27 acres.
- Clarity
- 7 ft
- Typical in August
- 74°F
- Max depth
- 28 ft
- Area
- 27 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Adams County
Mcginnis Lake is a 27-acre mesotrophic lake in Adams County, Wisconsin with a maximum depth of 28 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 2 documented fish species including Panfish and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 17 other monitored lakes in Adams County, Mcginnis Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-12. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7 ft. Phosphorus level: 20.8 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | 20.8 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mcginnis Lake
Compare lakeside cabins, hotels, and vacation rentals near Mcginnis Lake in Adams 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.
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Water Temperature
Mcginnis Lake typically sits around 74°F at the surface in August. Summer average is about 76°F. Usually warmest in Jun (about 78°F) and coldest in Apr (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 28 field readings (2024–2026) via the EPA Water Quality Portal. See the full Mcginnis Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28 ft |
| Surface Area | 27 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- McGinnis LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mcginnis 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.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2002. 1 station on file (most recent sample 2026).
Fish Species (DNR-rated)
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.95 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.78 µg/L/yr | 7 |
Reservoir Info (USACE NID)
Mcginnis Lake is a man-made reservoir impounded by the Mcginnis Lake (completed 1966), built primarily for recreation on the NEENAH CREEK; gravity-type dam, 15 ft tall and 450 ft long.
- Surface area
- 33 ac
- Normal storage
- 240 ac-ft
- Max storage
- 370 ac-ft
- Drainage area
- 0.2 sq mi
- Hazard class
- Low
- Owner
- Adams County
Source: USACE National Inventory of Dams, NID ID WI00238 · Operator website
County Ranking
Ranked #7 of 18 lakes in Adams County
Nearby Lakes in Adams County
Frequently asked questions about Mcginnis Lake
What is the water quality grade for Mcginnis Lake?
- Mcginnis Lake in Adams County, Wisconsin has a water quality grade of B (Good). Water clarity: 7 ft visibility. Phosphorus: 20.8 µg/L. Maximum depth: 28 ft. Surface area: 27 acres.
Is Mcginnis Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Mcginnis Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Mcginnis Lake?
- Mcginnis Lake typically sits around 74°F at the surface in August, from 28 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Mcginnis Lake?
- Mcginnis Lake has a maximum depth of 28 feet. The lake covers 27 acres.
What fish are in Mcginnis Lake?
- Fish species found in Mcginnis Lake include Panfish, Largemouth Bass. Mcginnis Lake is located in Adams County, Wisconsin.
Are there boat ramps on Mcginnis Lake?
- Mcginnis Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include McGinnis Lake. Public access is listed as yes.
Explore Mcginnis Lake across LakeGrade
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Where this data comes from
60 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_WQX60 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
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