Big Trout Lake
Crow Wing County, Minnesota1,366 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Big Trout Lake. Here is what has been measured.
- Oligotrophic
- Impaired · Mercury
- zebra mussel
- 128 ft max depth
- Public access
Big Trout Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.9 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 128 ft. Surface area: 1366.29 acres.
Minnesota DNR's Standard Survey on July 22, 2024 caught 0.67 walleye per gill net at Big Trout Lake. DNR survey details →
Free interactive depth-contour map of Big Trout Lake, reaching a maximum surveyed depth of 120 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Big Trout Lake is a 1,366-acre cold, clear oligotrophic lake in Crow Wing County, Minnesota with a maximum depth of 128 feet (52-foot average). Overall water quality is declining over recent sampling years. The lake supports 20 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Crow Wing County, Big Trout Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-14. Methodology: how these readings are compared.
Big Trout Lake covers about 1,400 acres in Crow Wing County. It has one public boat landing. The median ice-out date is April 29, which is when the open-water season begins. Vrbo is where to look for cabins and lake homes around Big Trout Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Big Trout Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.9 ft of visibility
- Boat launch1 documented ramp
- Fishing20 species recorded
- Ice seasonIce-out around Apr 29
- Deep water128 ft surveyed max depth
- Big water1,366 acres
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Big Trout Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Big Trout Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Trout Lake
These are the measurements Minnesota PCA publishes for Big Trout Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 16.9 ft down. Phosphorus 10 µg/L. Chlorophyll-a 2.1 µg/L. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 2.1µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Big Trout Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Trout Lake typically sits around 69°F at the surface in September. Summer average is about 75°F. Usually warmest in Jul (about 77°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (58°F) to its warmest (77°F).
Typical surface water temperature by month, from 14 field readings (2021–2025) via the EPA Water Quality Portal. See the full Big Trout Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 22, 2024 caught 0.67 walleye per gill net at Big Trout Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Trout Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
19 surveys on file from MN DNR Fisheries. Most recent: 2024-07-22 (Standard Survey).
19 surveys on file · most recent 2024-07-22 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluntnose Minnow | 32.30 | ||
| Bluegill | 15.67 | 2–8 in 2024-07-22 | 0.09 lb |
| Tullibee (Cisco) | 13.02 | 6–13 in 2024-07-22 | 0.14 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Bluegill
Tullibee (Cisco)
From the 2024-07-22 survey
Big trout is a 1,366 acre lake and is a part of the 14,000-acre Whitefish Chain of lakes in northern Crow Wing County. The maximum depth is 128 feet and 27% of the lake is 15 feet deep or less. On the east shore of the lake there is a U.S. Army Corps of Engineer's access off County Road 66. Big Trout is unique as it…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big 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 — Big TroutFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big Trout (0436)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Big TroutFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big TroutPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
128 ft
Average depth
52 ft
Surface area
1,366 acres
Shoreline
8.9 mi
Littoral zone
27%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Big Trout LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Big Trout Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Trout Lake in Crow Wing 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 Big Trout Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big 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.
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+0.59 µg/L/yr6 years
Chlorophyll-a
Worsening+0.05 µg/L/yr6 years
Ice season
Typical ice-out
Apr 29
Earliest Apr 7, 2021 · Latest May 14, 2013
Most recent ice-out
Apr 22
2025
7 observations · Minnesota PCA ice records
EPA Impairment Status
Big 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
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN18-0315-00 · Official waterbody report
Nearby Lakes in Crow Wing County
Frequently asked questions about Big Trout Lake
Where is Big Trout Lake?
- Big Trout Lake is a lake in Crow Wing County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Big Trout Lake?
- Big Trout Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.9 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 128 ft. Surface area: 1366.29 acres.
Is Big Trout Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Big Trout Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Big Trout Lake?
- Big Trout Lake typically sits around 69°F at the surface in September, from 14 EPA Water Quality Portal field readings (2021–2025). That is a typical value for the month, not a live reading.
How deep is Big Trout Lake?
- Big Trout Lake has a maximum depth of 128 feet and an average depth of 52 feet. The lake covers 1366.29 acres.
What fish are in Big Trout Lake?
- Fish species found in Big Trout Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, greater redhorse, green sunfish, hybrid sunfish, lake trout, lake whitefish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Big Trout Lake is located in Crow Wing County, Minnesota.
What did the DNR fisheries survey find at Big Trout Lake?
- Minnesota DNR's Standard Survey on July 22, 2024 caught 0.67 walleye per gill net at Big Trout Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Trout Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
When does Big Trout Lake thaw?
- Big Trout Lake typically has ice-out around Apr 29.
Are there boat ramps on Big Trout Lake?
- Big Trout Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Trout Lake. Public access is listed as yes.
Can I fish at Big Trout Lake?
- Big Trout Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Big Trout Lake across LakeQuality
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Where this data comes from
112 measurements from 4 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA112 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (4)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate