Hanson Lake
Lake County, MinnesotaLimited DataOligotrophic
Hanson Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota.
A TSI value of 37 puts Hanson Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 100 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. At 289 acres, Hanson Lake fits the Minnesota median for monitored lakes, with 5.6 miles of shoreline. Among the 142 graded lakes in Lake County, Hanson Lake ranks 7 — in the top quartile locally.
No invasive species are currently listed at Hanson Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 6, anchored by largemouth and/or smallmouth bass. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-07-02. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 16 ft down. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 100 ft |
| Surface Area | 289.43 acres |
| Shoreline Length | 5.6 mi |
| Littoral Zone | 15% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Hanson Lake (14-day solunar calendar)
→ Is it safe to eat fish from Hanson Lake? (mercury & PFAS guide)
→ Hanson 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 | -0.587 m/yr | 4 |
Location
County Ranking
Ranked #7 of 142 lakes in Lake County
Nearby Lakes in Lake County
More Minnesota Lake Rankings
Other Grade A Lakes in Minnesota
Oligotrophic Lakes in Minnesota
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 2025-08-01 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| LKW | 10.22 | 1.28 lb |
| CIS | 2.85 | 0.14 lb |
| BUB | 2.36 | 0.64 lb |
| Lake Trout | 2.21 | 2.4 lb |
| White Sucker | 1.50 | 2.93 lb |
| Smallmouth Bass | 1.45 | 2.09 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.
LKW
CIS
BUB
Lake Trout
From the 2025-08-01 survey
Temperature and dissolved oxygen measurements were collected from the deepest basin in Hanson Lake on August 1st, 2025. This was done to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Lake…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Hanson Lake. 1 report on file.
- —Fisheries Lake Survey — HansonFisheries Lake Survey · MN DNR LakeFinder
EPA Impairment Status
Hanson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN38-0206-00 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2023-07-02
Monitoring stations: 8