Crystal Lake
Otter Tail County, Minnesota1,413 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Crystal Lake. Here is what has been measured.
- Impaired · Mercury
- zebra mussel
- 55 ft max depth
- Public access
- Limited data
Crystal Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 55 ft. Surface area: 1412.94 acres.
Minnesota DNR's Targeted Survey on June 17, 2024 caught 0.17 walleye per trap net at Crystal Lake. DNR survey details →
Free interactive depth-contour map of Crystal Lake, reaching a maximum surveyed depth of 50 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Crystal Lake is a 1,413-acre lake in Otter Tail County, Minnesota with a maximum depth of 55 feet. The lake supports 17 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-15. Methodology: how these readings are compared.
What Crystal Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.2 ft of visibility
- Boat launch2 documented ramps
- Fishing17 species recorded
- Deep water55 ft surveyed max depth
- Big water1,413 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Crystal Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Crystal 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 Crystal Lake
These are the measurements Minnesota PCA publishes for Crystal 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 10.2 ft. Phosphorus 20 µg/L. Chlorophyll-a 4.8 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 20µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 4.8µg/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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Crystal Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Crystal Lake typically sits around 69°F at the surface in September. Summer average is about 70°F. Usually warmest in Aug (about 72°F) and coldest in May (about 52°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (52°F) to its warmest (72°F).
Typical surface water temperature by month, from 77 field readings (2016–2023) via the EPA Water Quality Portal. See the full Crystal Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Crystal Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (25,823 cells/mL) on April 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Targeted Survey on June 17, 2024 caught 0.17 walleye per trap net at Crystal Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Crystal 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 | 18.87 | 3–8 in 2024-06-17 | 0.18 lb |
| Bluntnose Minnow | 8.03 | ||
| Green Sunfish | 5.78 | 5–8 in 2024-06-17 | 0.15 lb |
| Northern Pike | 5.06 | 10–23 in 2024-06-17 | 1.35 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
Green Sunfish
Northern Pike
From the 2024-06-17 survey
A targeted survey of nearshore fish species in Crystal Lake, was conducted over several days, including June 17-18 and June 20, 2024, by Index of Biological Integrity (IBI) Program Staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Crystal Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CrystalFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Crystal (1050)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — CrystalFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CrystalPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
55 ft
Surface area
1,413 acres
Shoreline
8.9 mi
Littoral zone
48%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
9 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,302 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crystal LakePublic
- Lida Lake (North)Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Crystal Lake
Compare lakeside cabins, hotels, and vacation rentals near Crystal 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 Crystal Lake
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Follow Crystal Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Crystal 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.
EPA Impairment Status
Crystal Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MN56-0749-00 · Official waterbody report
Nearby Lakes in Otter Tail County
Frequently asked questions about Crystal Lake
Where is Crystal Lake?
- Crystal 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 Crystal Lake?
- Crystal Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 55 ft. Surface area: 1412.94 acres.
Is Crystal Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Crystal Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Crystal Lake?
- Crystal Lake typically sits around 69°F at the surface in September, from 77 EPA Water Quality Portal field readings (2016–2023). That is a typical value for the month, not a live reading.
How deep is Crystal Lake?
- Crystal Lake has a maximum depth of 55 feet. The lake covers 1412.94 acres.
What fish are in Crystal Lake?
- Fish species found in Crystal Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Crystal Lake is located in Otter Tail County, Minnesota.
What did the DNR fisheries survey find at Crystal Lake?
- Minnesota DNR's Targeted Survey on June 17, 2024 caught 0.17 walleye per trap net at Crystal Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Crystal Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
Does Crystal Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Crystal Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (25,823 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Crystal Lake?
- Crystal Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Crystal Lake, Lida Lake (North). Public access is listed as yes.
Can I fish at Crystal Lake?
- Crystal Lake has 2 documented boat landings 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
5 measurements from 2 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2022 - Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022
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 (2)
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
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