Larson Lake
Itasca County, Minnesota208 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Larson Lake. Here is what has been measured.
- Oligotrophic
- 177 ft max depth
- Public access
- Limited data
Larson Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 21 ft visibility. Phosphorus: 4 µg/L. Chlorophyll-a (algae): 1.5 µg/L. Maximum depth: 177 ft. Surface area: 208.18 acres.
Minnesota DNR's Standard Survey on August 10, 2020 caught 0.50 northern pike per gill net at Larson Lake. DNR survey details →
Larson Lake is a 208-acre cold, clear oligotrophic lake in Itasca County, Minnesota with a maximum depth of 177 feet. The lake supports 6 documented fish species including black bullhead, northern pike, and pumpkinseed. Public access is available with 1 public boat landing. Compared to the 71 other monitored lakes in Itasca County, Larson Lake ranks #49 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-14. Methodology: how these readings are compared.
What Larson Lake is good for
From access and monitoring records, not editorial picks.
- Clear water21 ft of visibility
- Boat launch1 documented ramp
- Fishing6 species recorded
- Deep water177 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
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 Larson 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 Larson Lake
These are the measurements Minnesota PCA publishes for Larson 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 21 ft down. Phosphorus 4 µg/L. Chlorophyll-a 1.5 µg/L. TSI 31.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 21ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 4µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.5µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 31 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Larson Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Larson Lake typically sits around 47°F at the surface in September. Summer average is about 48°F. Usually warmest in Jul (about 48°F) and coldest in May (about 44°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (44°F) to its warmest (48°F).
Typical surface water temperature by month, from 159 field readings (2021–2021) via the EPA Water Quality Portal. See the full Larson Lake water temperature breakdown →
Minnesota DNR's Standard Survey on August 10, 2020 caught 0.50 northern pike per gill net at Larson Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Larson Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2020-08-10 (Standard Survey).
12 surveys on file · most recent 2020-08-10 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 13.42 | 5–8 in 2020-08-10 | 0.12 lb |
| Pumpkinseed | 7.30 | 2–5 in 2020-08-10 | 0.08 lb |
| Black Bullhead | 3.58 | 4–7 in 2020-08-10 | 0.12 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.
Yellow Perch
Pumpkinseed
Black Bullhead
From the 2020-08-10 survey
Larson Lake is located 12 miles east of Effie, MN in the Big Fork River watershed. The lake has a surface area of 198 acres and a maximum depth of 177 feet. There is a DNR-administered access at the State Campground on the west side of the lake. The current lake management plan lists Splake as the primary species of…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Larson Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LarsonFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Larson (0648)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — LarsonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LarsonPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
177 ft
Surface area
208 acres
Shoreline
3.8 mi
Littoral zone
25%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,375 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Larson 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 Larson Lake
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Fish Species
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Fishing Larson Lake
Nearby Lakes in Itasca County
Frequently asked questions about Larson Lake
Where is Larson Lake?
- Larson Lake is a lake in Itasca County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Larson Lake?
- Larson Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 21 ft visibility. Phosphorus: 4 µg/L. Chlorophyll-a (algae): 1.5 µg/L. Maximum depth: 177 ft. Surface area: 208.18 acres.
Is Larson 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 Larson Lake?
- Larson Lake typically sits around 47°F at the surface in September, from 159 EPA Water Quality Portal field readings (2021–2021). That is a typical value for the month, not a live reading.
How deep is Larson Lake?
- Larson Lake has a maximum depth of 177 feet. The lake covers 208.18 acres.
What fish are in Larson Lake?
- Fish species found in Larson Lake include black bullhead, northern pike, pumpkinseed, splake, white sucker, yellow perch. Larson Lake is located in Itasca County, Minnesota.
What did the DNR fisheries survey find at Larson Lake?
- Minnesota DNR's Standard Survey on August 10, 2020 caught 0.50 northern pike per gill net at Larson Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Larson Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Larson Lake?
- Larson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Larson Lake. Public access is listed as yes.
Can I fish at Larson Lake?
- Larson 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 Larson Lake across LakeQuality
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Where this data comes from
13 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA13 samples · 2021
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 size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory