Trout Lake Deep
Trout Lake Deep in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10.7 ft visibility. Phosphorus: 9.7 µg/L. Chlorophyll-a (algae): 4.3 µg/L.
- Clarity
- 10.7 ft
- Typical in August
- 71°F
- Mean depth
- ~15 ft est.
- Type
- Mesotrophic
- Trend
- ↑ Improving
Next lake in Cook County
Trout Lake Deep is a mesotrophic lake in Cook County, Minnesota with an estimated average depth of about 15 feet. Water quality is graded A based on 2 sampling years through 2022. Overall water quality is improving over recent sampling years. Compared to the 43 other monitored lakes in Cook County, Trout Lake Deep ranks #31 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-20. Grade methodology: LakeGrade methodology.
Watch Trout Lake Deep water quality
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Swimming Safety
Grade onlyLimited data
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)
Good clarity, visible to about 10.7 ft. Phosphorus level: 9.7 µg/L. Chlorophyll-a: 4.3 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.7 ft | Not graded |
| Phosphorus | 9.7 µg/L | Good |
| Chlorophyll-a (Algae) | 4.3 µg/L | Good |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Trout Lake Deep
Compare lakeside cabins, hotels, and vacation rentals near Trout Lake Deep in Cook 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 Trout Lake Deep
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Water Temperature
Trout Lake Deep typically sits around 71°F at the surface in August. Summer average is about 69°F. Usually warmest in Jul (about 71°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 197 field readings (2010–2024) via the EPA Water Quality Portal. See the full Trout Lake Deep water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~15 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Trout Lake Deep.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Trout Lake Deep
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -5.255 m/yr | 4 |
| Phosphorus | ↑ Improving | -0.86 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.1 µg/L/yr | 4 |
County Ranking
Ranked #31 of 44 lakes in Cook County
Nearby Lakes in Cook County
Frequently asked questions about Trout Lake Deep
What is the water quality grade for Trout Lake Deep?
- Trout Lake Deep in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10.7 ft visibility. Phosphorus: 9.7 µg/L. Chlorophyll-a (algae): 4.3 µg/L.
Is Trout Lake Deep safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Trout Lake Deep has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Trout Lake Deep?
- Trout Lake Deep typically sits around 71°F at the surface in August, from 197 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Trout Lake Deep?
- No published bathymetric survey covers Trout Lake Deep, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 15 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Trout Lake Deep across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
161 measurements from 2 monitoring stations, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Grand Portage Reservation
GPC5_WQX106 samples · 2022 - 21GPBCH - Grand Portage Beaches (Tribal)
21GPBCH55 samples · 2020
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (2)
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)
Lake details from Minnesota DNR LakeFinder