Birch Lake
Birch Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 4 µg/L. Maximum depth: 45 ft. Surface area: 1267.19 acres.
- Clarity
- 14 ft
- Typical in August
- 72°F
- Max depth
- 45 ft
- Area
- 1,267 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 17
- Open water
- 215 days
Next lake in Cass County
Free interactive depth-contour map of Birch Lake, reaching a maximum surveyed depth of 45 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Birch Lake is a 1,267-acre mesotrophic lake in Cass County, Minnesota with a maximum depth of 45 feet (10-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 14 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 103 other monitored lakes in Cass County, Birch Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 14 ft. Phosphorus level: 12 µg/L. Chlorophyll-a: 4 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14 ft | Not graded |
| Phosphorus | 12 µg/L | Good |
| Chlorophyll-a (Algae) | 4 µg/L | Good |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Birch Lake
Compare lakeside cabins, hotels, and vacation rentals near Birch 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.
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Water Temperature
Birch Lake typically sits around 72°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 77°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 42 field readings (2011–2024) via the EPA Water Quality Portal. See the full Birch Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Birch Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (139,316 cells/mL) on May 11, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 45 ft |
| Average Depth | 10 ft |
| Surface Area | 1,267 acres |
| Shoreline Length | 15.3 mi |
| Littoral Zone | 60% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Birch LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Birch Lake
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2023-08-07 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 16.45 | 0.17 lb |
| Bluntnose Minnow | 8.51 | — |
| Northern Pike | 5.53 | 1.15 lb |
| Yellow Bass | 4.53 | 0.51 lb |
| Pumpkinseed | 3.97 | 0.15 lb |
| Yellow Perch | 3.56 | 0.17 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
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
Northern Pike
Yellow Bass
Pumpkinseed
From the 2023-08-07 survey
Birch Lake is a 1,267-acre lake with 15 miles of shoreline and a maximum depth of 45 feet located in Hackensack, MN. A City of Hackensack) owned public access is located on the east shore. The DNR has classified Minnesota's lakes into 43 different classes based on physical, chemical, and other characteristics. Birch…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Birch Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BirchFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Birch (1472)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BirchFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BirchPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.007 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.39 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.06 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (14 observations).
Estimated open water season: 215 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2017-04-08 (2017) | 2008-05-02 (2008) |
| Ice-In | 2019-11-07 (2019) | 2009-12-08 (2009) |
Most recent ice-out: 2017-04-08
County Ranking
Ranked #3 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Birch Lake
What is the water quality grade for Birch Lake?
- Birch Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 4 µg/L. Maximum depth: 45 ft. Surface area: 1267.19 acres.
Is Birch Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Birch Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Birch Lake?
- Birch Lake typically sits around 72°F at the surface in August, from 42 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Birch Lake?
- Birch Lake has a maximum depth of 45 feet and an average depth of 10 feet. The lake covers 1267.19 acres.
What fish are in Birch Lake?
- Fish species found in Birch Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Birch Lake is located in Cass County, Minnesota.
When does Birch Lake thaw?
- Birch Lake typically has ice-out around Apr 17. Ice typically forms around Nov 18. The open water season is approximately 215 days.
Does Birch Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Birch Lake (clouds, ice, or an off-season gap). The most recent reading was high (139,316 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Birch Lake?
- Birch Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Birch Lake. Public access is listed as yes.
Explore Birch Lake across LakeGrade
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Where this data comes from
128 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
MNPCA128 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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
Ice data from Minnesota DNR Climate