Margaret Lake
Cass County, MinnesotaEutrophic
Margaret Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.
At a TSI of 55, Margaret Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 26 ft puts Margaret Lake in the middle of Minnesota's depth distribution. At 251 acres, Margaret Lake fits the Minnesota median for monitored lakes, with 5.5 miles of shoreline. Within the 132 graded lakes of Cass County, Margaret Lake sits at rank 127, near the bottom of the county list.
Margaret Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The fishery includes walleye among the lake's 17 documented species — a notable draw for Minnesota anglers. The lake lacks a documented public access point, so visitor use is limited. The lake has a partial ice record — 16 observed ice-outs, centered near Apr 17. 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 2024-09-28. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.5 ft. Phosphorus level: 41 µg/L. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.5 ft | D |
| Phosphorus | 41 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 26 ft |
| Surface Area | 250.69 acres |
| Shoreline Length | 5.5 mi |
| Littoral Zone | 26% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Margaret Lake (14-day solunar calendar)
→ Is it safe to eat fish from Margaret Lake? (mercury & PFAS guide)
→ Margaret 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: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.093 m/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (25 observations).
Estimated open water season: 215 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2004-03-17 (2004) | 2013-05-10 (2013) |
| Ice-In | 2002-10-24 (2002) | 2001-12-05 (2001) |
Most recent ice-out: 2022-05-04
Location
County Ranking
Ranked #127 of 132 lakes in Cass County
Cleaner Lakes Within 30 Miles
Margaret Lake holds Grade C. 5 nearby lakes hold higher grades.
- AEdna LakeCrow Wing County · mi · Two grade letters higher (C → A)
- AUpper Gull LakeCass County · mi · Two grade letters higher (C → A)
- ARay LakeCass County · mi · Two grade letters higher (C → A)
- ARoy LakeCrow Wing County · mi · Two grade letters higher (C → A)
- ANisswa LakeCrow Wing County · mi · Two grade letters higher (C → A)
Nearby Lakes in Cass County
More Minnesota Lake Rankings
State Parks Near Margaret Lake
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2025-06-16 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 20.91 | 0.15 lb |
| Yellow Perch | 11.28 | 0.1 lb |
| Green Sunfish | 6.80 | 0.09 lb |
| GOS | 6.11 | 0.07 lb |
| Yellow Bass | 4.45 | 0.8 lb |
| Black Bullhead | 4.26 | 0.54 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
Yellow Perch
Green Sunfish
GOS
From the 2025-06-16 survey
Margaret Lake is a 222-acre lake near the city of Nisswa in Cass County. It is part of the Gull Lake Chain of Lakes, with access possible through a navigable channel connection from Upper Gull. Northern Pike is the primary management species and a special regulation is used to achieve our management objective on the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Margaret Lake. 2 reports on file.
- —Fisheries Lake Survey — MargaretFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Margaret (1534)Aquatic Plant Report · MN DNR LakeFinder
EPA Impairment Status
Margaret Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN11-0222-00 · 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: 2024-09-28
Monitoring stations: 3