Crystal Lake
Crystal Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. 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.
- Clarity
- 10.2 ft
- Typical in August
- 72°F
- Max depth
- 55 ft
- Area
- 1,413 acres
- Public access
- Yes
Next lake in Otter Tail County
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.
Why Crystal Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Crystal Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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. Grade methodology: LakeGrade methodology.
Watch Crystal Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Crystal Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 10.2 ft. Phosphorus level: 20 µg/L. Chlorophyll-a: 4.8 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.2 ft | Not graded |
| Phosphorus | 20 µg/L | Not graded |
| Chlorophyll-a (Algae) | 4.8 µg/L | Not graded |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay 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
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Crystal Lake typically sits around 72°F at the surface in August. 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.
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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 55 ft |
| Surface Area | 1,413 acres |
| Shoreline Length | 8.9 mi |
| Littoral Zone | 48% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crystal LakePublic
- Lida Lake (North)Public
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2024-06-17 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 18.87 | 0.18 lb |
| BKF | 11.04 | — |
| BCS | 8.58 | — |
| Bluntnose Minnow | 8.03 | — |
| Green Sunfish | 5.78 | 0.15 lb |
| Northern Pike | 5.06 | 1.35 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
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
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
Source: EPA ATTAINS assessment unit MN56-0749-00 · Official waterbody report
Graded lakes near Crystal Lake
Crystal Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Otter Tail County
Frequently asked questions about Crystal Lake
What is the water quality grade for Crystal Lake?
- Crystal Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. 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?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Crystal Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 4.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Crystal Lake?
- Crystal Lake typically sits around 72°F at the surface in August, 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.
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.
Explore Crystal Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Otter Tail County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Alexandria Lakes area
Top lakes and where to stay in the Detroit Lakes Area area
Top lakes and where to stay in the Otter Tail County area
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Red River of the North Watershed, ranked by water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Crystal Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
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)
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