Round Lake
Round Lake in Otter Tail County, Minnesota has a water quality grade of B (Good). Water clarity: 7.9 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Maximum depth: 36 ft. Surface area: 273.19 acres.
- Clarity
- 7.9 ft
- Typical in August
- 76°F
- Max depth
- 36 ft
- Area
- 273 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Otter Tail County
Round Lake is a 273-acre mesotrophic lake in Otter Tail County, Minnesota with a maximum depth of 36 feet. Water quality is graded B based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings. Compared to the 65 other monitored lakes in Otter Tail County, Round Lake ranks #49 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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7.9 ft. Phosphorus level: 21 µg/L. Chlorophyll-a: 7.1 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.9 ft | Not graded |
| Phosphorus | 21 µg/L | Good |
| Chlorophyll-a (Algae) | 7.1 µg/L | Good |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Round Lake
Compare lakeside cabins, hotels, and vacation rentals near Round 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
Round Lake typically sits around 76°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 78°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 25 field readings (2010–2021) via the EPA Water Quality Portal. See the full Round Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Round Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (50,119 cells/mL) on July 18, 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 | 36 ft |
| Surface Area | 273 acres |
| Shoreline Length | 2.4 mi |
| Littoral Zone | 81% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Rush Lake (West)Public
- Round LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Round 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
5 surveys on file from MN DNR Fisheries. Most recent: 2010-06-16 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 68.63 | 0.15 lb |
| Black Bullhead | 27.99 | 0.39 lb |
| Yellow Perch | 17.29 | 0.11 lb |
| Pumpkinseed | 10.21 | 0.18 lb |
| Northern Pike | 9.13 | 1.42 lb |
| Brown Bullhead | 7.81 | 0.4 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
Black Bullhead
Yellow Perch
Pumpkinseed
From the 2010-06-16 survey
Round Lake is a 262 acre eutrophic (fertile) lake located in central Otter Tail County approximately four miles north of Ottertail, MN. The immediate watershed consists primarily of hardwood woodlots and marshland. It has a maximum depth of 36 feet; however, 84% of the lake is 15 feet or less in depth. The secchi disk…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Round Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — RoundFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — RoundFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — RoundPublic 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 | +0.1 m/yr | 6 |
| Phosphorus | ↑ Improving | -2.34 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.02 µg/L/yr | 6 |
County Ranking
Ranked #49 of 66 lakes in Otter Tail County
Nearby Lakes With Higher Grades
Round Lake holds Grade B. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Otter Tail County
Frequently asked questions about Round Lake
What is the water quality grade for Round Lake?
- Round Lake in Otter Tail County, Minnesota has a water quality grade of B (Good). Water clarity: 7.9 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Maximum depth: 36 ft. Surface area: 273.19 acres.
Is Round Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Round Lake has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 7.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Round Lake?
- Round Lake typically sits around 76°F at the surface in August, from 25 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
How deep is Round Lake?
- Round Lake has a maximum depth of 36 feet. The lake covers 273.19 acres.
What fish are in Round Lake?
- Fish species found in Round Lake include black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Round Lake is located in Otter Tail County, Minnesota.
Does Round Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Round Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (50,119 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Round Lake?
- Round Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Rush Lake (West), Round Lake. Public access is listed as yes.
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Where this data comes from
88 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
MNPCA88 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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory