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C

Lunar Lake

Lake County, MinnesotaLimited DataMesotrophic

The LakeGrade rubric puts Lunar Lake at a C: clarity at 8.0 ft, phosphorus readings still being added, and a TSI of 47 signal an intermediate trophic state.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake's 60 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. At 62 acres, Lunar Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Within the 142 graded lakes of Lake County, Lunar Lake sits at rank 110, near the bottom of the county list.

Lunar Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Lunar Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. 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 2023-07-01. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Moderate clarity, visible to about 8 ft. Trophic State Index: 47.

MetricValueGrade
Water Clarity (Secchi Depth)8 ftC
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)47Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth60 ft
Surface Area62.31 acres
Shoreline Length2.2 mi
Littoral Zone40%
Public AccessNo

Water Quality Trend: Declining

Based on 4 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.755 m/yr4
See year-by-year chart →

Location

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County Ranking

Ranked #110 of 142 lakes in Lake County

Nearby Lakes in Lake County

DNR Fisheries Survey Summary

3 surveys on file from MN DNR Fisheries. Most recent: 2025-07-31 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
White Sucker7.200.91 lb
Lake Trout2.803.94 lb
Green Sunfish2.400.15 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

From the 2025-07-31 survey

Temperature and dissolved oxygen measurements were collected from the deepest basin in Lunar Lake on July 31st, 2025. This was done to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake. Lake Trout…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

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

EPA Impairment Status

Lunar Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Source: EPA ATTAINS assessment unit MN38-0166-00 · Official waterbody report · Matched by proximity (0.59 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Lake details from Minnesota DNR LakeFinder

Most recent sample: 2023-07-01

Monitoring stations: 1