Marion Lake
Marion Lake in McLeod County, Minnesota has a water quality grade of F (Algae-prone). Phosphorus: 71 µg/L. Chlorophyll-a (algae): 73 µg/L. Maximum depth: 15.2 ft. Surface area: 520.43 acres.
- Typical in August
- 82°F
- Max depth
- 15.2 ft
- Area
- 520 acres
- Type
- Eutrophic
- Public access
- Yes
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Marion Lake →
Next lake in McLeod County
Marion Lake is a 520-acre productive, nutrient-rich eutrophic lake in McLeod County, Minnesota with a maximum depth of 15 feet (10-foot average). Water quality is graded F based on 2 sampling years through 2021. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 4 other monitored lakes in McLeod County, Marion Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-19. Grade methodology: LakeGrade methodology.
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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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
No clarity data. Phosphorus level: 71 µg/L. Chlorophyll-a: 73 µg/L. Trophic State Index: 69.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 71 µg/L | Poor |
| Chlorophyll-a (Algae) | 73 µg/L | Poor |
| Trophic State Index (TSI) | 69 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Marion Lake
Compare lakeside cabins, hotels, and vacation rentals near Marion Lake in McLeod 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 Marion Lake are listed below.
Top-rated places to stay near Marion Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Marion Lake typically sits around 82°F at the surface in August. Summer average is about 76°F. Usually warmest in Aug (about 82°F) and coldest in Jun (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2016–2021) via the EPA Water Quality Portal. See the full Marion Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Marion Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was very high (1,169,499 cells/mL) on July 18, 2026.
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 | 15.2 ft |
| Average Depth | 10 ft |
| Surface Area | 520 acres |
| Shoreline Length | 6.7 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Marion Lake (East)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Marion Lake
DNR Fisheries Survey Summary
26 surveys on file from MN DNR Fisheries. Most recent: 2025-09-10 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 40.19 | 0.16 lb |
| SUN | 40.18 | — |
| Walleye | 33.81 | 1.32 lb |
| Black Crappie | 31.22 | 0.26 lb |
| Black Bullhead | 28.46 | 0.88 lb |
| Largemouth Bass | 20.67 | 0.99 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.
Yellow Perch
Walleye
Black Crappie
Black Bullhead
From the 2025-09-10 survey
A targeted survey (fall nighttime electrofishing) was conducted on Marion Lake on September 10th, 2025, to evaluate young of the year (YOY) and yearling Walleye abundance. A total of 101 YOY were sampled for a catch rate of 101.0 fish/hr., which was above the lake's historical (1994 to 2025) median (30.0 fish/hr.).…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Marion Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MarionFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — MarionFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MarionPublic Water Access Sites · MN DNR LakeFinder
Reservoir Info (USACE NID)
Marion Lake is a man-made reservoir impounded by the Lake Marion (completed 1948), built primarily for other on the Buffalo Creek-TR; other-type dam, 10 ft tall and 37 ft long.
- Surface area
- 520 ac
- Normal storage
- 173 ac-ft
- Max storage
- 404 ac-ft
- Drainage area
- 7.4 sq mi
- Hazard class
- Low
- Owner
- McLeod County Sportsman's Club
Source: USACE National Inventory of Dams, NID ID MN00156 · Operator website
EPA Impairment Status
Marion 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 MN43-0084-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Marion Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Brownton WwtpBrownton · 4.2 mi away · NPDES MN0022951Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #3 of 5 lakes in McLeod County
Nearby Lakes With Higher Grades
Marion Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in McLeod County
Frequently asked questions about Marion Lake
What is the water quality grade for Marion Lake?
- Marion Lake in McLeod County, Minnesota has a water quality grade of F (Algae-prone). Phosphorus: 71 µg/L. Chlorophyll-a (algae): 73 µg/L. Maximum depth: 15.2 ft. Surface area: 520.43 acres.
Is Marion Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Marion Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 73 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Marion Lake?
- Marion Lake typically sits around 82°F at the surface in August, from 12 EPA Water Quality Portal field readings (2016–2021). That is a typical value for the month, not a live reading.
How deep is Marion Lake?
- Marion Lake has a maximum depth of 15.2 feet and an average depth of 10 feet. The lake covers 520.43 acres.
What fish are in Marion Lake?
- Fish species found in Marion Lake include black bullhead, black crappie, bluegill, brown bullhead, channel catfish, common carp, hybrid sunfish, largemouth bass, northern pike, sunfish, walleye, yellow bullhead, yellow perch. Marion Lake is located in McLeod County, Minnesota.
Does Marion Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Marion Lake (clouds, ice, or an off-season gap). The most recent reading was very high (1,169,499 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Marion Lake?
- Marion Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Marion Lake (East). Public access is listed as yes.
Explore Marion Lake across LakeGrade
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Where this data comes from
10 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA10 samples · 2021
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory