Trout Lake
Trout Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18.4 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Maximum depth: 77 ft. Surface area: 258.91 acres.
- Clarity
- 18.4 ft
- Typical in August
- 55°F
- Max depth
- 77 ft
- Area
- 259 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- May 6
Next lake in Cook County
Trout Lake is a 259-acre cold, clear oligotrophic lake in Cook County, Minnesota with a maximum depth of 77 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 6 documented fish species including brook trout, lake trout, and rainbow smelt. Public access is available with 1 public boat landing. Compared to the 43 other monitored lakes in Cook County, Trout Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-07. 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)
Crystal clear, you can see 18.4 ft down. Phosphorus level: 9 µg/L. Chlorophyll-a: 1.3 µg/L. Trophic State Index: 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18.4 ft | Not graded |
| Phosphorus | 9 µg/L | Good |
| Chlorophyll-a (Algae) | 1.3 µg/L | Good |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Trout Lake
Compare lakeside cabins, hotels, and vacation rentals near Trout Lake 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.
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Water Temperature
Trout Lake typically sits around 55°F at the surface in August. Summer average is about 53°F. Usually warmest in Aug (about 55°F) and coldest in Mar (about 36°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,423 field readings (2010–2025) via the EPA Water Quality Portal. See the full Trout Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Trout Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (539,511 cells/mL) on June 1, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 77 ft |
| Surface Area | 259 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 23% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Kimball LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Trout 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.
DNR Fisheries Survey Summary
20 surveys on file from MN DNR Fisheries. Most recent: 2025-08-18 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 15.64 | 0.13 lb |
| RBS | 9.85 | 0.06 lb |
| PRD | 7.12 | — |
| GOS | 2.98 | 0.07 lb |
| CNM | 2.87 | — |
| Lake Trout | 2.76 | 1.1 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
RBS
PRD
GOS
From the 2025-08-18 survey
A targeted survey of nearshore fish species in Trout Lake was conducted on August 18- 20, 2025, by Lake Biological Monitoring and Assessment Program staff. Ten nearshore sampling sites were evenly spaced around the lake, and each were sampled by backpack electrofishing, mini-fyke nets, and seining with a 15-foot…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Trout Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — TroutFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Trout (1591)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — TroutFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — TroutPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.428 m/yr | 5 |
| Phosphorus | ↓ Declining | +0.77 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.05 µg/L/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (8 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-04-08 (2012) | 2014-05-21 (2014) |
Most recent ice-out: 2017-04-26
EPA Impairment Status
Trout 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 MN16-0049-00 · Official waterbody report
County Ranking
Ranked #6 of 44 lakes in Cook County
Nearby Lakes in Cook County
Frequently asked questions about Trout Lake
What is the water quality grade for Trout Lake?
- Trout Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18.4 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Maximum depth: 77 ft. Surface area: 258.91 acres.
Is Trout Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Trout Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 1.3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Trout Lake?
- Trout Lake typically sits around 55°F at the surface in August, from 1,423 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Trout Lake?
- Trout Lake has a maximum depth of 77 feet. The lake covers 258.91 acres.
What fish are in Trout Lake?
- Fish species found in Trout Lake include brook trout, lake trout, rainbow smelt, rainbow trout, white sucker, yellow perch. Trout Lake is located in Cook County, Minnesota.
When does Trout Lake thaw?
- Trout Lake typically has ice-out around May 6.
Does Trout Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Trout Lake (clouds, ice, or an off-season gap). The most recent reading was high (539,511 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Trout Lake?
- Trout Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Kimball Lake. Public access is listed as yes.
Explore Trout Lake across LakeGrade
6.2 mi away · 50 ft
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Where this data comes from
79 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA79 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- 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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate