Barnum Lake
Cass County, Minnesota151 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Barnum Lake. Here is what has been measured.
- Oligotrophic
- 30 ft max depth
- Public access
Barnum Lake in Cass County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.1 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 3 µg/L. Maximum depth: 30 ft. Surface area: 151.34 acres.
Minnesota DNR's Standard Survey on June 11, 2001 caught 10.17 northern pike per gill net at Barnum Lake. DNR survey details →
Barnum Lake is a 151-acre cold, clear oligotrophic lake in Cass County, Minnesota with a maximum depth of 30 feet. The lake supports 8 documented fish species including black crappie, bluegill, and largemouth bass. Public access is available. Compared to the 103 other monitored lakes in Cass County, Barnum Lake ranks #56 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Methodology: how these readings are compared.
Barnum Lake covers about 150 acres in Cass County. The median ice-out date is April 17, which is when the open-water season begins. Vrbo is where to look for cabins and lake homes around Barnum Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Barnum Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.1 ft of visibility
- Fishing8 species recorded
- Ice seasonIce-out around Apr 17
- Deep water30 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 Barnum 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 Barnum Lake
These are the measurements Minnesota PCA publishes for Barnum 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 16.1 ft down. Phosphorus 9 µg/L. Chlorophyll-a 3 µg/L. TSI 38.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 9µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3µg/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. | 38 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Barnum Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Barnum Lake typically sits around 66°F at the surface in September. Summer average is about 74°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 66°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (66°F) to its warmest (78°F).
Typical surface water temperature by month, from 30 field readings (2011–2021) via the EPA Water Quality Portal. See the full Barnum Lake water temperature breakdown →
Minnesota DNR's Standard Survey on June 11, 2001 caught 10.17 northern pike per gill net at Barnum Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Barnum Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 2001-06-11 (Standard Survey).
2 surveys on file · most recent 2001-06-11 (Standard Survey)
25 years old| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 42.58 | 2–8 in 2001-06-11 | 0.23 lb |
| Largemouth Bass | 12.02 | 2–21 in 2001-06-11 | 0.95 lb |
| Pumpkinseed | 6.92 | 3–7 in 2001-06-11 | 0.19 lb |
| Smallmouth Bass | 5.42 | 4–17 in 2001-06-11 | 0.76 lb |
| Yellow Perch | 4.78 | 5–9 in 2001-06-11 | 0.22 lb |
| Black Crappie | 3.76 | 5–11 in 2001-06-11 | 0.35 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
Pumpkinseed
Smallmouth Bass
From the 2001-06-11 survey
Barnum Lake has an area of 134 acres and a maximum depth of 30 feet. About two-thirds of Barnum Lake is 15 feet or less in depth. Barnum Lake is located about nine miles east and three miles north of Hackensack, MN. The Minnesota Department of Natural Resources (MN DNR) has classified Minnesota's lakes into 43…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Barnum Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BarnumFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
30 ft
Surface area
151 acres
Shoreline
4.5 mi
Littoral zone
56%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
3 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,335 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Barnum Lake
Compare lakeside cabins, hotels, and vacation rentals near Barnum Lake in Cass 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 Barnum Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Barnum Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Stable+0.09 µg/L/yr6 years
Chlorophyll-a
Stable+0.01 µg/L/yr6 years
Ice season
Typical ice-out
Apr 17
Earliest Mar 24, 2012 · Latest May 8, 2013
Typical ice-in
Nov 24
Earliest Nov 3, 2004 · Latest Dec 19, 2001
Most recent ice-out
Apr 18
2025
56 observations · Minnesota PCA ice records
Nearby Lakes in Cass County
Frequently asked questions about Barnum Lake
Where is Barnum Lake?
- Barnum Lake is a lake in Cass County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Barnum Lake?
- Barnum Lake in Cass County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.1 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 3 µg/L. Maximum depth: 30 ft. Surface area: 151.34 acres.
Is Barnum 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 Barnum Lake?
- Barnum Lake typically sits around 66°F at the surface in September, from 30 EPA Water Quality Portal field readings (2011–2021). That is a typical value for the month, not a live reading.
How deep is Barnum Lake?
- Barnum Lake has a maximum depth of 30 feet. The lake covers 151.34 acres.
What fish are in Barnum Lake?
- Fish species found in Barnum Lake include black crappie, bluegill, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, yellow perch. Barnum Lake is located in Cass County, Minnesota.
What did the DNR fisheries survey find at Barnum Lake?
- Minnesota DNR's Standard Survey on June 11, 2001 caught 10.17 northern pike per gill net at Barnum Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Barnum Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
When does Barnum Lake thaw?
- Barnum Lake typically has ice-out around Apr 17. Ice typically forms around Nov 24. The open water season is approximately 221 days.
Can I fish at Barnum Lake?
- Public access to Barnum Lake is listed as yes on the lake record. 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.
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Where this data comes from
92 measurements from 2 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
MNPCA92 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 (2)
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
Ice data from Minnesota DNR Climate