Tetagouche Lake
Tetagouche Lake in Lake County, Minnesota has a water quality grade of A (Excellent). Water clarity: 7.2 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 20 ft. Surface area: 66.56 acres.
- Clarity
- 7.2 ft
- Typical in August
- 70°F
- Max depth
- 20 ft
- Area
- 67 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- No
Next lake in Lake County
Tetagouche Lake is a 67-acre mesotrophic lake in Lake County, Minnesota with a maximum depth of 20 feet. Water quality is graded A based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 2 documented fish species including northern pike and yellow perch. No public access — the lake is private or restricted. Compared to the 34 other monitored lakes in Lake County, Tetagouche Lake ranks #11 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-07. 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 7.2 ft. Phosphorus level: 17 µg/L. Chlorophyll-a: 4.8 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.2 ft | Not graded |
| Phosphorus | 17 µg/L | Good |
| Chlorophyll-a (Algae) | 4.8 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Tetagouche Lake
Compare lakeside cabins, hotels, and vacation rentals near Tetagouche Lake in Lake County, Minnesota — 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 Tetagouche Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Tetagouche Lake typically sits around 70°F at the surface in August. Summer average is about 70°F. Usually warmest in Jul (about 72°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 43 field readings (2022–2023) via the EPA Water Quality Portal. See the full Tetagouche Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 20 ft |
| Surface Area | 67 acres |
| Shoreline Length | 1.8 mi |
| Littoral Zone | 99% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Tetagouche Lake
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2022-07-11 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 12.26 | 0.13 lb |
| Northern Pike | 6.98 | 2.15 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Yellow Perch
Northern Pike
From the 2022-07-11 survey
Tettagouche Lake is a 67 acre lake with a maximum depth of 20 feet located entirely within Tettagouche State Park. Minnesota residents do not need a fishing license to fish on the lake because the lake is completely contained within a state park, but must comply with all other fishing regulations. Motorized watercraft…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Tetagouche Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — TetagoucheFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Tetagouche (0768)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.16 m/yr | 2 |
| Phosphorus | ↓ Declining | +3 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +0.2 µg/L/yr | 2 |
EPA Impairment Status
Tetagouche Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN38-0231-00 · Official waterbody report
County Ranking
Ranked #11 of 35 lakes in Lake County
Nearby Lakes in Lake County
Frequently asked questions about Tetagouche Lake
What is the water quality grade for Tetagouche Lake?
- Tetagouche Lake in Lake County, Minnesota has a water quality grade of A (Excellent). Water clarity: 7.2 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 20 ft. Surface area: 66.56 acres.
Is Tetagouche Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Tetagouche Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Tetagouche Lake?
- Tetagouche Lake typically sits around 70°F at the surface in August, from 43 EPA Water Quality Portal field readings (2022–2023). That is a typical value for the month, not a live reading.
How deep is Tetagouche Lake?
- Tetagouche Lake has a maximum depth of 20 feet. The lake covers 66.56 acres.
What fish are in Tetagouche Lake?
- Fish species found in Tetagouche Lake include northern pike, yellow perch. Tetagouche Lake is located in Lake County, Minnesota.
Explore Tetagouche Lake across LakeGrade
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Moderate nutrients, good water quality
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Planning a trip around Apostle Islands?
Tetagouche Lake is about 39 miles from Apostle Islands National Lakeshore. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Apostle Islands →More Minnesota Lake Rankings
State Parks Near Tetagouche Lake
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
45 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA45 samples · 2022–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- 2120 B ~ Color in Water by Visual Comparison
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder