Big Lasalle Lake
Clearwater County, Minnesota235 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Big Lasalle Lake. Here is what has been measured.
- Mesotrophic
- 48 ft max depth
- Public access
Big Lasalle Lake in Clearwater County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 3.2 µg/L. Maximum depth: 48 ft. Surface area: 235.22 acres.
Minnesota DNR's Targeted Survey on July 6, 2021 caught 17.68 largemouth bass per hour of electrofishing at Big Lasalle Lake. DNR survey details →
Big Lasalle Lake is a 235-acre mesotrophic lake in Clearwater County, Minnesota with a maximum depth of 48 feet. Overall water quality is improving over recent sampling years. The lake supports 14 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Big Lasalle Lake ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. Methodology: how these readings are compared.
What Big Lasalle Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.2 ft of visibility
- Boat launch1 documented ramp
- Fishing14 species recorded
- Ice seasonIce-out around Apr 24
- Deep water48 ft surveyed max depth
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. Check local advisories before you swim.
Whether Big Lasalle 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 Lasalle Lake
These are the measurements Minnesota PCA publishes for Big Lasalle Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10.2 ft. Phosphorus 10.5 µg/L. Chlorophyll-a 3.2 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3.2µg/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. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Big Lasalle Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Lasalle Lake typically sits around 60°F at the surface in September. Summer average is about 59°F. Usually warmest in Aug (about 61°F) and coldest in Jun (about 57°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (57°F) to its warmest (61°F).
Typical surface water temperature by month, from 417 field readings (2019–2025) via the EPA Water Quality Portal. See the full Big Lasalle Lake water temperature breakdown →
Minnesota DNR's Targeted Survey on July 6, 2021 caught 17.68 largemouth bass per hour of electrofishing at Big Lasalle Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lasalle Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2023-07-31 (Targeted Survey).
8 surveys on file · most recent 2023-07-31 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 14.56 | 3–8 in 2021-06-29 | 0.16 lb |
| Green Sunfish | 10.40 | 5–7 in 2021-06-29 | 0.25 lb |
| Bluntnose Minnow | 7.34 |
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
Green Sunfish
From the 2023-07-31 survey
A temperature-dissolved oxygen profile was collected in the deepest basin on Big LaSalle Lake on July 31, 2023, to evaluate the amount of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee. Based on the profile, the top of the thermocline (i.e., the location in the water…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Lasalle 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 LaSalleFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big LaSalle (1317)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Big LaSalleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big LaSallePublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
48 ft
Surface area
235 acres
Shoreline
3.3 mi
Littoral zone
17%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Big LaSalle 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 Lasalle Lake
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Top-rated places to stay near Big Lasalle Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big Lasalle Lake
- → Big Lasalle Lake fishing: DNR survey catch rates, species & stocking
- → Big Lasalle Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → Big Lasalle Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from Big Lasalle Lake? (mercury & PFAS guide)
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+0.29 µg/L/yr6 years
Chlorophyll-a
Improving-0.34 µg/L/yr6 years
Ice season
Typical ice-out
Apr 24
Earliest Apr 15, 1992 · Latest May 6, 1996
Typical ice-in
Nov 18
Earliest Nov 7, 1991 · Latest Dec 10, 1999
Most recent ice-out
May 1
2018
14 observations · Minnesota PCA ice records
Nearby Lakes in Clearwater County
Frequently asked questions about Big Lasalle Lake
Where is Big Lasalle Lake?
- Big Lasalle Lake is a lake in Clearwater 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 Lasalle Lake?
- Big Lasalle Lake in Clearwater County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 3.2 µg/L. Maximum depth: 48 ft. Surface area: 235.22 acres.
Is Big Lasalle Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Big Lasalle Lake?
- Big Lasalle Lake typically sits around 60°F at the surface in September, from 417 EPA Water Quality Portal field readings (2019–2025). That is a typical value for the month, not a live reading.
How deep is Big Lasalle Lake?
- Big Lasalle Lake has a maximum depth of 48 feet. The lake covers 235.22 acres.
What fish are in Big Lasalle Lake?
- Fish species found in Big Lasalle Lake include black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Big Lasalle Lake is located in Clearwater County, Minnesota.
What did the DNR fisheries survey find at Big Lasalle Lake?
- Minnesota DNR's Targeted Survey on July 6, 2021 caught 17.68 largemouth bass per hour of electrofishing at Big Lasalle Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lasalle Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Big Lasalle Lake thaw?
- Big Lasalle Lake typically has ice-out around Apr 24. Ice typically forms around Nov 18. The open water season is approximately 208 days.
Are there boat ramps on Big Lasalle Lake?
- Big Lasalle Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big LaSalle Lake. Public access is listed as yes.
Can I fish at Big Lasalle Lake?
- Big Lasalle 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 Lasalle Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Clearwater County
Species activity outlook by water temperature and season
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Where this data comes from
85 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
MNPCA85 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
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
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate