Big Mcdonald Lake
Otter Tail County, Minnesota992 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Big Mcdonald Lake. Here is what has been measured.
- Oligotrophic
- Impaired · Impaired biota (cause unknown)
- zebra mussel
- 46 ft max depth
- Public access
Big Mcdonald Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 17.4 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 3.2 µg/L. Maximum depth: 46 ft. Surface area: 991.7 acres.
Minnesota DNR's Standard Survey on August 19, 2025 caught 9.67 walleye per gill net at Big Mcdonald Lake. DNR survey details →
Big Mcdonald Lake is a 992-acre cold, clear oligotrophic lake in Otter Tail County, Minnesota with a maximum depth of 46 feet. Overall water quality is improving over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 65 other monitored lakes in Otter Tail County, Big Mcdonald Lake ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
Big Mcdonald Lake covers about 990 acres in Otter Tail County. It has one public boat landing. The median ice-out date is April 17, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around Big Mcdonald Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Big Mcdonald Lake is good for
From access and monitoring records, not editorial picks.
- Clear water17.4 ft of visibility
- Boat launch1 documented ramp
- Fishing15 species recorded
- Ice seasonIce-out around Apr 17
- Deep water46 ft surveyed max depth
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Big Mcdonald Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
Whether Big Mcdonald Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Mcdonald Lake
These are the measurements Minnesota PCA publishes for Big Mcdonald Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 17.4 ft down. Phosphorus 12 µg/L. Chlorophyll-a 3.2 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 17.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3.2µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 39 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Big Mcdonald Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Mcdonald Lake typically sits around 64°F at the surface in September. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in May (about 54°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (54°F) to its warmest (75°F).
Typical surface water temperature by month, from 34 field readings (2010–2025) via the EPA Water Quality Portal. See the full Big Mcdonald Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Big Mcdonald Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (22,491 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Standard Survey on August 19, 2025 caught 9.67 walleye per gill net at Big Mcdonald Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Mcdonald Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-08-19 (Standard Survey).
9 surveys on file · most recent 2025-08-19 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Largemouth Bass | 26.18 | 4–17 in 2025-08-19 | 0.68 lb |
| Yellow Bullhead | 21.11 | 7–14 in 2025-08-19 | 0.72 lb |
| Bluegill | 19.53 | 2–9 in 2025-08-19 | 0.23 lb |
| Bluntnose Minnow | 12.14 | ||
| Green Sunfish | 6.31 |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Largemouth Bass
Yellow Bullhead
Bluegill
From the 2025-08-19 survey
Big McDonald Lake is a 935-acre mesotrophic (moderately fertile) lake located in north-central Otter Tail County approximately nine miles west of Perham, MN. Big McDonald Lake is located within the Otter Tail River Watershed. The immediate watershed is primarily composed of agricultural land interspersed with hardwood…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Mcdonald Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Big McDonaldFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Big McDonaldFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big McDonaldPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
46 ft
Surface area
992 acres
Shoreline
5.8 mi
Littoral zone
37%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
21 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,342 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Big McDonald LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Big Mcdonald Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Mcdonald Lake in Otter Tail 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.
Top-rated places to stay near Big Mcdonald Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big Mcdonald Lake
- → Big Mcdonald Lake fishing: DNR survey catch rates, species & stocking
- → Big Mcdonald Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → Big Mcdonald Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from Big Mcdonald Lake? (mercury & PFAS guide)
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 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+0.24 µg/L/yr6 years
Chlorophyll-a
Improving-0.11 µg/L/yr6 years
Ice season
Typical ice-out
Apr 17
Earliest Apr 2, 2021 · Latest May 6, 2022
Typical ice-in
Nov 27
Earliest Nov 7, 2007 · Latest Dec 19, 2015
Most recent ice-out
Apr 5
2024
24 observations · Minnesota PCA ice records
EPA Impairment Status
Big Mcdonald Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0386-01 · Official waterbody report
Nearby Lakes in Otter Tail County
Frequently asked questions about Big Mcdonald Lake
Where is Big Mcdonald Lake?
- Big Mcdonald Lake is a lake in Otter Tail County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Big Mcdonald Lake?
- Big Mcdonald Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 17.4 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 3.2 µg/L. Maximum depth: 46 ft. Surface area: 991.7 acres.
Is Big Mcdonald Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Big Mcdonald Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
What is the water temperature of Big Mcdonald Lake?
- Big Mcdonald Lake typically sits around 64°F at the surface in September, from 34 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Big Mcdonald Lake?
- Big Mcdonald Lake has a maximum depth of 46 feet. The lake covers 991.7 acres.
What fish are in Big Mcdonald Lake?
- Fish species found in Big Mcdonald Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, yellow bullhead, yellow perch. Big Mcdonald Lake is located in Otter Tail County, Minnesota.
What did the DNR fisheries survey find at Big Mcdonald Lake?
- Minnesota DNR's Standard Survey on August 19, 2025 caught 9.67 walleye per gill net at Big Mcdonald Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Mcdonald Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Big Mcdonald Lake thaw?
- Big Mcdonald Lake typically has ice-out around Apr 17. Ice typically forms around Nov 27. The open water season is approximately 224 days.
Does Big Mcdonald Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Big Mcdonald Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (22,491 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Big Mcdonald Lake?
- Big Mcdonald Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big McDonald Lake. Public access is listed as yes.
Can I fish at Big Mcdonald Lake?
- Big Mcdonald Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
263 measurements from 4 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
MNPCA263 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Phosphorus by Colorimetry
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (4)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate