Margaret Lake
Margaret Lake in Cass County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 5.5 ft visibility. Phosphorus: 38.5 µg/L. Chlorophyll-a (algae): 21.5 µg/L. Maximum depth: 26 ft. Surface area: 250.69 acres.
- Clarity
- 5.5 ft
- Typical in August
- 75°F
- Max depth
- 26 ft
- Area
- 251 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- No
- Ice-out
- Apr 17
- Open water
- 215 days
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Margaret Lake →
Next lake in Cass County
Margaret Lake is a 251-acre productive, nutrient-rich eutrophic lake in Cass County, Minnesota with a maximum depth of 26 feet. Water quality is graded D based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 17 documented fish species including black crappie, bluegill, and bowfin (dogfish). No public access — the lake is private or restricted. Compared to the 103 other monitored lakes in Cass County, Margaret Lake ranks #102 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-27. Grade methodology: LakeGrade methodology.
Watch Margaret Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyLimited data
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 5.5 ft. Phosphorus level: 38.5 µg/L. Chlorophyll-a: 21.5 µg/L. Trophic State Index: 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.5 ft | Not graded |
| Phosphorus | 38.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 21.5 µg/L | Poor |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Margaret Lake
Compare lakeside cabins, hotels, and vacation rentals near Margaret 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Margaret Lake are listed below.
Top-rated places to stay near Margaret Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Margaret Lake typically sits around 75°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 70°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 31 field readings (2022–2025) via the EPA Water Quality Portal. See the full Margaret Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Margaret Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (420,727 cells/mL) on November 1, 2025.
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 | 26 ft |
| Surface Area | 251 acres |
| Shoreline Length | 5.5 mi |
| Littoral Zone | 26% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Margaret Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
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.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MargaretFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Margaret (1534)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.079 m/yr | 6 |
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
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
County Ranking
Ranked #102 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Margaret Lake
What is the water quality grade for Margaret Lake?
- Margaret Lake in Cass County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 5.5 ft visibility. Phosphorus: 38.5 µg/L. Chlorophyll-a (algae): 21.5 µg/L. Maximum depth: 26 ft. Surface area: 250.69 acres.
Is Margaret Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Margaret Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 21.5 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Margaret Lake?
- Margaret Lake typically sits around 75°F at the surface in August, from 31 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Margaret Lake?
- Margaret Lake has a maximum depth of 26 feet. The lake covers 250.69 acres.
What fish are in Margaret Lake?
- Fish species found in Margaret Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, greater redhorse, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Margaret Lake is located in Cass County, Minnesota.
When does Margaret Lake thaw?
- Margaret Lake typically has ice-out around Apr 17. Ice typically forms around Nov 18. The open water season is approximately 215 days.
Does Margaret Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Margaret Lake (clouds, ice, or an off-season gap). The most recent reading was high (420,727 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Explore Margaret Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Cass County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Brainerd Lakes area
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Pine River Watersheds (Brainerd Lakes), ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Margaret Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
322 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA322 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (3)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate