Green Lake
Kandiyohi County, MinnesotaMesotrophic
On the LakeGrade rubric, Green Lake pulls an A: clarity at 13.1 ft and 14 µg/L of phosphorus put it in the top bracket for Minnesota. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.
The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. At 110 ft of maximum depth, Green Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 5,569 acres, Green Lake is one of the larger lakes in Kandiyohi County, with 12.0 miles of shoreline supporting multiple distinct use patterns. Within Kandiyohi County's 35 graded waters, Green Lake sits at rank 3, near the top of the local distribution.
Zebra mussel presence at Green Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Green Lake's fishery is anchored by muskellunge, with 22 documented species in total — a destination water for muskie anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Green Lake more than two dozen times, putting the median around Apr 16 — a useful baseline for tracking climate trends. 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 2024-09-12. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 13.1 ft. Phosphorus level: 14 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.1 ft | B |
| Phosphorus | 14 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 110 ft |
| Average Depth | 21 ft |
| Surface Area | 5.6K acres |
| Shoreline Length | 12 mi |
| Littoral Zone | 37% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Green Lake (14-day solunar calendar)
→ Is it safe to eat fish from Green Lake? (mercury & PFAS guide)
→ Green Lake fishing regulations (limits, seasons, special rules)
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: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.269 m/yr | 5 |
| Phosphorus | ↓ Declining | +1.1 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (300 observations).
Estimated open water season: 230 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-15 (2024) | 2013-05-08 (2013) |
| Ice-In | 1932-11-17 (1932) | 2024-01-04 (2024) |
Most recent ice-out: 2025-03-31
Location
County Ranking
Ranked #3 of 35 lakes in Kandiyohi County
Nearby Lakes in Kandiyohi County
More Minnesota Lake Rankings
State Parks Near Green Lake
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Green Lake With Nearby Lakes
Kandiyohi County · Grade C
Kandiyohi County · Grade C
Kandiyohi County · Grade B
Kandiyohi County · Grade D
Kandiyohi County · Grade B
Kandiyohi County · Grade F
DNR Fisheries Survey Summary
44 surveys on file from MN DNR Fisheries. Most recent: 2025-09-12 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 25.46 | 0.12 lb |
| BKS | 17.19 | — |
| Walleye | 11.44 | 1.03 lb |
| Bluntnose Minnow | 8.57 | — |
| Yellow Perch | 5.36 | 0.12 lb |
| Rock Bass | 5.28 | 0.38 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
Walleye
Yellow Perch
Rock Bass
From the 2025-09-12 survey
A standard survey in Green Lake was conducted during mid-September of 2025 using lake survey gillnets and trapnets. Standard surveys were done during the last week of July or first week of August prior to 2021. Targeted surveys were conducted to determine if September gillnetting would more effectively sample the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Green Lake. 3 reports on file.
- —Fisheries Lake Survey — GreenFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — GreenFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — GreenPublic Water Access Sites · MN DNR LakeFinder
Reservoir Info (USACE NID)
Green Lake is a man-made reservoir impounded by the Green Lake (completed 1938), built primarily for recreation on the CROW RIVER MIDDLE FORK; gravity-type dam, 9 ft tall and 62 ft long.
- Surface area
- 5,560 ac
- Normal storage
- 11,000 ac-ft
- Max storage
- 11,700 ac-ft
- Drainage area
- 149 sq mi
- Hazard class
- Low
- Owner
- MNDNR-Wildlife
Source: USACE National Inventory of Dams, NID ID MN00370 · Operator website
EPA Impairment Status
Green Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN34-0079-00 · 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
Ice data from Minnesota DNR Climate
Most recent sample: 2024-09-12
Monitoring stations: 1