Skip to main content
LakeQuality
C

Leech Lake

Cass County, MinnesotaLimited DataMesotrophic

Leech Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI near 45 places Leech Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Leech Lake ranks 124 of 133 in Cass County — at the lower end of the locally monitored distribution.

Leech Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The state fisheries records do not list documented species for Leech Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at Leech Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been logged at Leech Lake more than two dozen times, putting the median around Apr 28 — a useful baseline for tracking climate trends. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-10-23. Grade methodology: LakeGrade methodology.

Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Moderate clarity, visible to about 9 ft. Trophic State Index: 45.

MetricValueGrade
Water Clarity (Secchi Depth)9 ftC
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)45Mesotrophic

Moderate nutrients, good water quality

Invasive Species

Eurasian watermilfoilstarry stonewortzebra mussel

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.31 m/yr2

Ice Season

Historical ice data from Minnesota DNR (74 observations).

Typical Ice-Out
Apr 28
Typical Ice-In
Nov 14

Estimated open water season: 200 days

EarliestLatest
Ice-Out1945-04-09 (1945)1950-05-23 (1950)
Ice-In2018-11-13 (2018)2021-11-25 (2021)

Most recent ice-out: 2022-05-08

Location

Loading map…

County Ranking

Ranked #124 of 133 lakes in Cass County

Nearby Lakes in Cass County

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Leech Lake. 1 report on file.

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Ice data from Minnesota DNR Climate

Most recent sample: 2021-10-23

Monitoring stations: 1