Six Lake
Six Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 21 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 140 ft. Surface area: 196.53 acres.
- Clarity
- 21 ft
- Typical in August
- 73°F
- Max depth
- 140 ft
- Area
- 197 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 21
Next lake in Otter Tail County
Six Lake is a 197-acre cold, clear oligotrophic lake in Otter Tail County, Minnesota with a maximum depth of 140 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 11 documented fish species including black crappie, bluegill, and hybrid sunfish. Public access is available. Compared to the 65 other monitored lakes in Otter Tail County, Six Lake ranks #42 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 21 ft down. Phosphorus level: 7 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 34.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 21 ft | Not graded |
| Phosphorus | 7 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 34 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Six Lake
Compare lakeside cabins, hotels, and vacation rentals near Six 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
Six Lake typically sits around 73°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 77°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2011–2023) via the EPA Water Quality Portal. See the full Six Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 140 ft |
| Surface Area | 197 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 33% |
| 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 Six 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
7 surveys on file from MN DNR Fisheries. Most recent: 2019-07-09 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 29.78 | 0.16 lb |
| Yellow Bass | 13.75 | 0.66 lb |
| Hybrid Sunfish | 4.52 | 0.27 lb |
| Northern Pike | 3.09 | 1.64 lb |
| Largemouth Bass | 2.83 | 0.53 lb |
| Yellow Perch | 2.49 | 0.14 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
Yellow Bass
Hybrid Sunfish
Northern Pike
From the 2019-07-09 survey
Lake Six is a 188-acre oligotrophic (low fertility) lake located in north-central Otter Tail County approximately two miles north of Vergas, MN. The immediate watershed is composed of mixed hardwood woodlots. The maximum depth is 140 feet; however, 34% of the lake is 15 feet or less in depth. The secchi disk reading…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Six Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — SixFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Six (1140)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — SixFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — SixPublic 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 | ↑ Improving | +0.551 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.86 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.13 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (6 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2003-04-16 (2003) | 2004-04-24 (2004) |
| Ice-In | 2006-12-11 (2006) | 2006-12-11 (2006) |
Most recent ice-out: 2007-04-23
EPA Impairment Status
Six 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 MN03-0265-00 · Official waterbody report · Matched by proximity (2.92 km)
County Ranking
Ranked #42 of 66 lakes in Otter Tail County
Nearby Lakes in Otter Tail County
Frequently asked questions about Six Lake
What is the water quality grade for Six Lake?
- Six Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 21 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 140 ft. Surface area: 196.53 acres.
Is Six Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Six Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Six Lake?
- Six Lake typically sits around 73°F at the surface in August, from 29 EPA Water Quality Portal field readings (2011–2023). That is a typical value for the month, not a live reading.
How deep is Six Lake?
- Six Lake has a maximum depth of 140 feet. The lake covers 196.53 acres.
What fish are in Six Lake?
- Fish species found in Six Lake include black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Six Lake is located in Otter Tail County, Minnesota.
When does Six Lake thaw?
- Six Lake typically has ice-out around Apr 21.
Explore Six Lake across LakeGrade
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Where this data comes from
101 measurements from 2 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
MNPCA101 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 (2)
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