Little Mcdonald Lake
Little Mcdonald Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 26.5 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 109 ft. Surface area: 1316.02 acres.
- Clarity
- 26.5 ft
- Typical in August
- 75°F
- Max depth
- 109 ft
- Area
- 1,316 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 20
- Open water
- 230 days
Next lake in Otter Tail County
Free interactive depth-contour map of Little Mcdonald Lake, reaching a maximum surveyed depth of 100 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Little Mcdonald Lake is a 1,316-acre cold, clear oligotrophic lake in Otter Tail County, Minnesota with a maximum depth of 109 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 14 documented fish species including black bullhead, black crappie, and bluegill. Public access is available. Compared to the 65 other monitored lakes in Otter Tail County, Little Mcdonald Lake ranks #26 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 26.5 ft down. Phosphorus level: 7 µg/L. Chlorophyll-a: 1.8 µg/L. Trophic State Index: 33.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 26.5 ft | Not graded |
| Phosphorus | 7 µg/L | Good |
| Chlorophyll-a (Algae) | 1.8 µg/L | Good |
| Trophic State Index (TSI) | 33 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Little Mcdonald Lake
Compare lakeside cabins, hotels, and vacation rentals near Little 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.
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Water Temperature
Little Mcdonald Lake typically sits around 75°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 76°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 40 field readings (2010–2025) via the EPA Water Quality Portal. See the full Little Mcdonald Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Little Mcdonald Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (20,137 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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 109 ft |
| Surface Area | 1,316 acres |
| Shoreline Length | 8.5 mi |
| Littoral Zone | 31% |
| Public Access | Yes |
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 Little Mcdonald 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
10 surveys on file from MN DNR Fisheries. Most recent: 2020-08-24 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 36.73 | 0.14 lb |
| MMS | 9.17 | — |
| Bluntnose Minnow | 6.65 | — |
| Walleye | 5.74 | 3.42 lb |
| Rock Bass | 5.64 | 0.35 lb |
| BMS | 5.46 | — |
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
Rock Bass
From the 2020-08-24 survey
Little McDonald Lake is a 1,174-acre mestrophic (moderately fertile) lake located in north-central Otter Tail County approximately six miles west of Perham, MN. The immediate watershed is composed of agricultural land interspersed with hardwood woodlots. The maximum depth is 109 feet; however, 35% of the lake is 15…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Little 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 — Little McDonaldFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Little McDonaldFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Little McDonaldPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.094 m/yr | 6 |
| Phosphorus | → Stable | +0.03 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.08 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (110 observations).
Estimated open water season: 230 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2000-04-05 (2000) | 1996-05-11 (1996) |
| Ice-In | 2018-11-21 (2018) | 2024-01-02 (2024) |
Most recent ice-out: 2025-04-20
EPA Impairment Status
Little 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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0328-00 · Official waterbody report
County Ranking
Ranked #26 of 66 lakes in Otter Tail County
Nearby Lakes in Otter Tail County
Frequently asked questions about Little Mcdonald Lake
What is the water quality grade for Little Mcdonald Lake?
- Little Mcdonald Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 26.5 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 109 ft. Surface area: 1316.02 acres.
Is Little Mcdonald Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Little Mcdonald Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 1.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Little Mcdonald Lake?
- Little Mcdonald Lake typically sits around 75°F at the surface in August, from 40 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Little Mcdonald Lake?
- Little Mcdonald Lake has a maximum depth of 109 feet. The lake covers 1316.02 acres.
What fish are in Little Mcdonald Lake?
- Fish species found in Little Mcdonald Lake include black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Little Mcdonald Lake is located in Otter Tail County, Minnesota.
When does Little Mcdonald Lake thaw?
- Little Mcdonald Lake typically has ice-out around Apr 20. Ice typically forms around Dec 6. The open water season is approximately 230 days.
Does Little Mcdonald Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Little Mcdonald Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (20,137 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
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Where this data comes from
150 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
MNPCA150 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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