Long Lake
Otter Tail County, Minnesota1,289 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Long Lake. Here is what has been measured.
- Mesotrophic
- zebra mussel
- 128 ft max depth
- Public access
Long Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 12.3 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.4 µg/L. Maximum depth: 128 ft. Surface area: 1289.21 acres.
Minnesota DNR's Targeted Survey on June 17, 2024 caught 3.11 walleye per gill net at Long Lake. DNR survey details →
Free interactive depth-contour map of Long Lake, reaching a maximum surveyed depth of 120 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Long Lake is a 1,289-acre mesotrophic lake in Otter Tail County, Minnesota with a maximum depth of 128 feet. The lake supports 16 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing. Compared to the 65 other monitored lakes in Otter Tail County, Long Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
What Long Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.3 ft of visibility
- Boat launch1 documented ramp
- Fishing16 species recorded
- Ice seasonIce-out around Apr 15
- Deep water128 ft surveyed max depth
- Big water1,289 acres
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Long 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 Long Lake
These are the measurements Minnesota PCA publishes for Long Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 12.3 ft. Phosphorus 20 µg/L. Chlorophyll-a 4.4 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 12.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 20µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 4.4µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Long Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Targeted Survey on June 17, 2024 caught 3.11 walleye per gill net at Long Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2024-06-17 (Targeted Survey).
12 surveys on file · most recent 2024-06-17 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 34.24 | 3–8 in 2024-06-17 | 0.14 lb |
| Bluntnose Minnow | 24.58 | ||
| Largemouth Bass | 10.27 | 10–18 in 2024-06-17 | 0.88 lb |
| Golden Shiner | 9.26 | 5 in 1999-06-21 | 0.04 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.
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
Golden Shiner
From the 2024-06-17 survey
Long Lake is a 1,273-acre lake located in north-central Otter Tail County. The southwest shoreline of the lake abuts the city of Vergas, MN. Long Lake is composed of two distinct basins. The west basin is characteristic of an oligotrophic lake (i.e., deep and unfertile) while the east basin is characteristic of a…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LongFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
128 ft
Surface area
1,289 acres
Shoreline
12.6 mi
Littoral zone
41%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
71 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,339 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Long LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long 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.
Top-rated places to stay near Long Lake
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Follow Long Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Long 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.
Ice season
Typical ice-out
Apr 15
Earliest Apr 13, 2015 · Latest May 11, 2013
Most recent ice-out
Apr 13
2015
5 observations · Minnesota PCA ice records
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Long Lake under Clean Water Act (NPDES) discharge permits.
- Schlauderaff EnterprisesFrazee · 1.5 mi away · NPDES MN0071684
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Otter Tail County
Frequently asked questions about Long Lake
Where is Long Lake?
- Long 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 Long Lake?
- Long Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 12.3 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.4 µg/L. Maximum depth: 128 ft. Surface area: 1289.21 acres.
Is Long Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Long Lake?
- Long Lake has a maximum depth of 128 feet. The lake covers 1289.21 acres.
What fish are in Long Lake?
- Fish species found in Long Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Long Lake is located in Otter Tail County, Minnesota.
What did the DNR fisheries survey find at Long Lake?
- Minnesota DNR's Targeted Survey on June 17, 2024 caught 3.11 walleye per gill net at Long Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
When does Long Lake thaw?
- Long Lake typically has ice-out around Apr 15.
Are there boat ramps on Long Lake?
- Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Long Lake. Public access is listed as yes.
Can I fish at Long Lake?
- Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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
186 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
MNPCA186 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)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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