Deer Lake
Deer Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 26 ft. Surface area: 447.07 acres.
- Clarity
- 12.3 ft
- Typical in August
- 75°F
- Max depth
- 26 ft
- Area
- 447 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 20
- Open water
- 218 days
Next lake in Otter Tail County
Deer Lake is a 447-acre mesotrophic lake in Otter Tail County, Minnesota with a maximum depth of 26 feet. Water quality is graded A based on 2 sampling years through 2025. Water clarity is improving over recent sampling years. The lake supports 16 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, Deer Lake ranks #8 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)
Good clarity, visible to about 12.3 ft. Phosphorus level: 21 µg/L. Chlorophyll-a: 4.8 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.3 ft | Not graded |
| Phosphorus | 21 µg/L | Good |
| Chlorophyll-a (Algae) | 4.8 µg/L | Good |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Deer Lake
Compare lakeside cabins, hotels, and vacation rentals near Deer 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
Deer Lake typically sits around 75°F at the surface in August. Summer average is about 73°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.
Typical surface water temperature by month, from 52 field readings (2018–2021) via the EPA Water Quality Portal.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Deer Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (173,780 cells/mL) on July 6, 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 | 26 ft |
| Surface Area | 447 acres |
| Shoreline Length | 3.9 mi |
| Littoral Zone | 68% |
| Public Access | Yes |
Recreation & Access
- Deer LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Deer 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: 2024-06-10 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 25.12 | 0.12 lb |
| Largemouth Bass | 9.66 | 0.78 lb |
| Pumpkinseed | 4.68 | 0.17 lb |
| Yellow Perch | 3.78 | 0.2 lb |
| Northern Pike | 3.33 | 1.06 lb |
| Yellow Bass | 3.31 | 0.73 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
Largemouth Bass
Pumpkinseed
Yellow Perch
From the 2024-06-10 survey
Deer Lake is a 457-acre mesotrophic (moderately fertile) lake located in central Otter Tail County approximately five miles north of Battle Lake, MN. Deer Lake is connected to Otter Tail Lake via the Otter Tail River. The immediate watershed is composed primarily of agricultural land interspersed with hardwood…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Deer Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — DeerFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Deer (1164)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — DeerFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — DeerPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.086 m/yr | 6 |
| Phosphorus | → Stable | -0.33 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.3 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (13 observations).
Estimated open water season: 218 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-15 (2024) | 2023-04-30 (2023) |
| Ice-In | 2018-11-10 (2018) | 2016-12-07 (2016) |
Most recent ice-out: 2024-03-15
EPA Impairment Status
Deer Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN56-0378-01 · Official waterbody report · Matched by proximity (1.33 km)
County Ranking
Ranked #8 of 66 lakes in Otter Tail County
Nearby Lakes in Otter Tail County
Frequently asked questions about Deer Lake
What is the water quality grade for Deer Lake?
- Deer Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 26 ft. Surface area: 447.07 acres.
Is Deer Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Deer Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Deer Lake?
- Deer Lake typically sits around 75°F at the surface in August, from 52 EPA Water Quality Portal field readings (2018–2021). That is a typical value for the month, not a live reading.
How deep is Deer Lake?
- Deer Lake has a maximum depth of 26 feet. The lake covers 447.07 acres.
What fish are in Deer Lake?
- Fish species found in Deer Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, lake sturgeon, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Deer Lake is located in Otter Tail County, Minnesota.
When does Deer Lake thaw?
- Deer Lake typically has ice-out around Apr 20. Ice typically forms around Nov 24. The open water season is approximately 218 days.
Does Deer Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Deer Lake (clouds, ice, or an off-season gap). The most recent reading was high (173,780 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Deer Lake?
- Deer Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Deer Lake. Public access is listed as yes.
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Where this data comes from
75 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA75 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 (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
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