Leech Lake
Leech Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12.5 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 2.7 µg/L.
- Clarity
- 12.5 ft
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 28
- Open water
- 200 days
Next lake in Cass County
Leech Lake is a mesotrophic lake in Cass County, Minnesota. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 103 other monitored lakes in Cass County, Leech Lake ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-10. Grade methodology: LakeGrade methodology.
Watch Leech Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Leech Lake Water Quality Report Card (2026)
A printable one-page report card for Leech Lake: grade, clarity, phosphorus, algae, multi-year trend, depth, and fish — with sources.
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)
Good clarity, visible to about 12.5 ft. Phosphorus level: 12 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.5 ft | Not graded |
| Phosphorus | 12 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Leech Lake
Compare lakeside cabins, hotels, and vacation rentals near Leech Lake in Cass 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 Leech 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 →
Current Conditions
USGS snapshot Jul 6, 2026, 4:30 AM from gauge 05205900 (Leech Lake at Sugar Point Near Federal Dam, MN). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Leech Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (40,179 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Leech 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 Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Leech Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — Leech (Main Basin)Public 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 | +0.14 m/yr | 6 |
| Phosphorus | → Stable | -0.09 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.2 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (74 observations).
Estimated open water season: 200 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 1945-04-09 (1945) | 1950-05-23 (1950) |
| Ice-In | 2018-11-13 (2018) | 2021-11-25 (2021) |
Most recent ice-out: 2022-05-08
County Ranking
Ranked #13 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Leech Lake
What is the water quality grade for Leech Lake?
- Leech Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12.5 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 2.7 µg/L.
Is Leech Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Leech Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.7 µg/L. Always check local health department advisories before swimming.
How deep is Leech Lake?
- The available depth estimate for Leech Lake is shallower than its measured water clarity, which cannot be right, so no depth is shown.
When does Leech Lake thaw?
- Leech Lake typically has ice-out around Apr 28. Ice typically forms around Nov 14. The open water season is approximately 200 days.
What is the water level at Leech Lake?
- The USGS snapshot on this page for Leech Lake is 94.71 ft of gage height, recorded Jul 6, 2026, 4:30 AM at gauge 05205900. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Does Leech Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Leech Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (40,179 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Explore Leech Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Cass County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Brainerd Lakes area
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Pine River Watersheds (Brainerd Lakes), ranked by water quality
Moderate nutrients, good water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
588 measurements from 11 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
MNPCA566 samples · 2020–2025 - Leech Lake Band of Ojibwe
LEECHLAK_WQX22 samples · 2022–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (11)
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)
Ice data from Minnesota DNR Climate