Hanska Lake
Brown County, MinnesotaHypereutrophic
On the LakeGrade rubric Hanska Lake fails the cutoffs — a TSI of 78 and persistent algal pressure put it in the bottom tier. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. A maximum depth of 16 ft puts Hanska Lake in the middle of Minnesota's depth distribution. Hanska Lake covers 1,795 acres alongside 21.3 miles of shoreline, large enough that conditions can vary meaningfully between bays. Within Brown County's 7 graded lakes, Hanska Lake ranks 5 — below the local median, though not at the bottom.
No invasive species are currently listed at Hanska Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Hanska Lake, one of 16 fish species on record for the lake. A documented public access point at Hanska Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a long ice-out record — 78 observations on file, with a median ice-out around Apr 3. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-11. Grade methodology: LakeGrade methodology.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 1 ft of visibility. Phosphorus level: 218 µg/L. Chlorophyll-a: 99.6 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | F |
| Phosphorus | 218 µg/L | F |
| Chlorophyll-a (Algae) | 99.6 µg/L | F |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 16 ft |
| Average Depth | 4.5 ft |
| Surface Area | 1.8K acres |
| Shoreline Length | 21.3 mi |
| Littoral Zone | 99% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Hanska Lake (14-day solunar calendar)
→ Is it safe to eat fish from Hanska Lake? (mercury & PFAS guide)
→ Hanska Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.024 m/yr | 4 |
| Phosphorus | ↓ Declining | +12.5 µg/L/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (82 observations).
Estimated open water season: 249 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2007-03-01 (2007) | 1951-04-26 (1951) |
| Ice-In | 2007-11-22 (2007) | 2004-12-13 (2004) |
Most recent ice-out: 2008-04-11
Location
County Ranking
Ranked #5 of 7 lakes in Brown County
Nearby Lakes in Brown County
More Minnesota Lake Rankings
State Parks Near Hanska Lake
Other Grade F Lakes in Minnesota
DNR Fisheries Survey Summary
15 surveys on file from MN DNR Fisheries. Most recent: 2025-08-18 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 74.83 | 0.58 lb |
| Fathead Minnow | 55.27 | 0.01 lb |
| Black Crappie | 32.09 | 0.25 lb |
| OSS | 19.60 | 0.04 lb |
| Bluegill | 16.75 | 0.3 lb |
| Walleye | 15.02 | 1.32 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.
Black Bullhead
Black Crappie
Bluegill
Walleye
From the 2025-08-18 survey
Hanska is a large-sized lake (1,794 acres) located west of the City of Hanska in Brown County. A large state-owned access with paved parking and a double cement boat ramp is present on the southeast shore. There are also two smaller boat ramps at the northwest end of the lake (Geiger Point and Godahl). There are…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Hanska Lake. 3 reports on file.
- —Fisheries Lake Survey — HanskaFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — HanskaFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — HanskaPublic Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2023-10-11
Monitoring stations: 3