Clamshell Lake
Crow Wing County, Minnesota211 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Clamshell Lake. Here is what has been measured.
- Mesotrophic
- zebra mussel
- 44 ft max depth
- Public access
Clamshell Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 15.1 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 44 ft. Surface area: 211.06 acres.
Minnesota DNR's Standard Survey on June 10, 2024 caught 10.67 northern pike per gill net at Clamshell Lake. DNR survey details →
Clamshell Lake is a 211-acre mesotrophic lake in Crow Wing County, Minnesota with a maximum depth of 44 feet. Overall water quality is declining over recent sampling years. The lake supports 18 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, Clamshell Lake ranks #50 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-14. Methodology: how these readings are compared.
Clamshell Lake covers about 210 acres in Crow Wing County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Clamshell Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Clamshell Lake is good for
From access and monitoring records, not editorial picks.
- Clear water15.1 ft of visibility
- Boat launch1 documented ramp
- Fishing18 species recorded
- Deep water44 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 Clamshell 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 Clamshell Lake
These are the measurements Minnesota PCA publishes for Clamshell 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 15.1 ft down. Phosphorus 16 µg/L. Chlorophyll-a 2.7 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 15.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 16µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 2.7µg/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 Clamshell Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Clamshell Lake typically sits around 63°F at the surface in September. Summer average is about 64°F. Usually warmest in Aug (about 65°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 (65°F).
Typical surface water temperature by month, from 203 field readings (2017–2025) via the EPA Water Quality Portal. See the full Clamshell Lake water temperature breakdown →
Minnesota DNR's Standard Survey on June 10, 2024 caught 10.67 northern pike per gill net at Clamshell Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Clamshell 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
11 surveys on file from MN DNR Fisheries. Most recent: 2024-08-05 (Targeted Survey).
11 surveys on file · most recent 2024-08-05 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 22.08 | 2–8 in 2024-06-10 | 0.13 lb |
| Largemouth Bass | 5.69 | 6–15 in 2024-06-10 | 0.92 lb |
| Green Sunfish | 5.61 | 3–5 in 2024-06-10 | 0.1 lb |
| Yellow Bullhead | 5.60 | 5–11 in 2024-06-10 | 0.44 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
Largemouth Bass
Green Sunfish
Yellow Bullhead
From the 2024-08-05 survey
Temperature and dissolved oxygen profiles were collected in the deepest basin in Clamshell Lake on August 14, 2024, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Whitefish, the most sensitive coldwater species present in this lake (Cisco are also present).…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Clamshell Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ClamshellFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — ClamshellPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
44 ft
Surface area
211 acres
Shoreline
6.5 mi
Littoral zone
67%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Clamshell 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 Clamshell Lake
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Top-rated places to stay near Clamshell Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Clamshell 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
Worsening6 years
Phosphorus
Worsening+0.76 µg/L/yr6 years
Chlorophyll-a
Stable+0.01 µg/L/yr6 years
Nearby Lakes in Crow Wing County
Frequently asked questions about Clamshell Lake
Where is Clamshell Lake?
- Clamshell 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 Clamshell Lake?
- Clamshell Lake in Crow Wing County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 15.1 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 44 ft. Surface area: 211.06 acres.
Is Clamshell 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 Clamshell Lake?
- Clamshell Lake typically sits around 63°F at the surface in September, from 203 EPA Water Quality Portal field readings (2017–2025). That is a typical value for the month, not a live reading.
How deep is Clamshell Lake?
- Clamshell Lake has a maximum depth of 44 feet. The lake covers 211.06 acres.
What fish are in Clamshell Lake?
- Fish species found in Clamshell Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, lake whitefish, largemouth bass, northern pike, northern sunfish, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Clamshell Lake is located in Crow Wing County, Minnesota.
What did the DNR fisheries survey find at Clamshell Lake?
- Minnesota DNR's Standard Survey on June 10, 2024 caught 10.67 northern pike per gill net at Clamshell Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Clamshell 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.
Are there boat ramps on Clamshell Lake?
- Clamshell Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Clamshell Lake. Public access is listed as yes.
Can I fish at Clamshell Lake?
- Clamshell 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 Clamshell Lake across LakeQuality
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Where this data comes from
108 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
MNPCA108 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 (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