Mule Lake
Otter Tail County, Minnesota53 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Mule Lake. Here is what has been measured.
- 31 ft max depth
- Public access
- Limited data
Mule Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 17.1 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Maximum depth: 31 ft. Surface area: 53.36 acres.
Minnesota DNR's Standard Survey on June 22, 1992 caught 1.00 northern pike per gill net at Mule Lake. DNR survey details →
Mule Lake is a 53-acre lake in Otter Tail County, Minnesota with a maximum depth of 31 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-08-02. Methodology: how these readings are compared.
What Mule Lake is good for
From access and monitoring records, not editorial picks.
- Clear water17.1 ft of visibility
- Deep water31 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Mule 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 Mule Lake
These are the measurements Minnesota PCA publishes for Mule 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 17.1 ft down. Phosphorus 8 µg/L. Chlorophyll-a 1.3 µg/L. TSI 35.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 17.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 8µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 1.3µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 35 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Mule Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on June 22, 1992 caught 1.00 northern pike per gill net at Mule Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mule 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
1 survey on file from MN DNR Fisheries. Most recent: 1992-06-22 (Standard Survey).
1 survey on file · most recent 1992-06-22 (Standard Survey)
34 years old| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 63.63 | 0.17 lb | |
| Yellow Bullhead | 11.25 | 0.2 lb | |
| Brown Bullhead | 9.25 | 0.27 lb | |
| Black Crappie | 7.25 | 0.3 lb | |
| Pumpkinseed | 5.75 | 0.1 lb | |
| Hybrid Sunfish | 3.50 | 0.37 lb |
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.
From the 1992-06-22 survey
Mule Lake is included in class 33 of the MN DNR lake classification system. Other area lakes in this class include: Anderson, Belmont, Jim, and Tonseth. Northern pike abundance is below normal for this lake class with a gill net catch rate of 1.0 per lift. The average weight of individual northern pike was 2.9 pounds.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mule Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MuleFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — MuleFish Stocking History · MN DNR LakeFinder
Lake Details
Max depth
31 ft
Surface area
53 acres
Shoreline
2.3 mi
Littoral zone
64%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
10 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,362 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
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Stays near Mule Lake
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Fishing Mule Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Nearby Lakes in Otter Tail County
Frequently asked questions about Mule Lake
Where is Mule Lake?
- Mule 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 Mule Lake?
- Mule Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 17.1 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Maximum depth: 31 ft. Surface area: 53.36 acres.
Is Mule Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Mule Lake?
- Mule Lake has a maximum depth of 31 feet. The lake covers 53.36 acres.
What did the DNR fisheries survey find at Mule Lake?
- Minnesota DNR's Standard Survey on June 22, 1992 caught 1.00 northern pike per gill net at Mule Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mule 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.
Can I fish at Mule Lake?
- Public access to Mule Lake is listed as yes on the lake record. 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
4 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder