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D

Long Lake

Kandiyohi County, MinnesotaEutrophic

Long Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

At a TSI of 65, Long Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 16 ft puts Long Lake in the middle of Minnesota's depth distribution. With 1,573 acres of surface and 12.5 miles of shoreline, Long Lake is a large water by Minnesota standards — recreational pressure is spread across a long shoreline. Long Lake sits at rank 19 of 35 in Kandiyohi County, in the lower half of the local distribution.

Zebra mussel presence at Long Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Walleye are documented at Long Lake, one of 16 fish species on record for the lake. A documented public access point at Long Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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 2024-09-07. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Very murky, less than 3 ft of visibility. Phosphorus level: 88 µg/L. Trophic State Index: 65.

MetricValueGrade
Water Clarity (Secchi Depth)3 ftF
Phosphorus88 µg/LD
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)65Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth16 ft
Surface Area1.6K acres
Shoreline Length12.5 mi
Littoral Zone95%
Public AccessYes

Fish Species

bigmouth buffalo,black bullhead,black crappie,bluegill,brown bullhead,common carp,green sunfish,hybrid sunfish,largemouth bass,northern pike,orangespotted sunfish,pumpkinseed,smallmouth bass,walleye,yellow bullhead,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Long Lake (14-day solunar calendar)

→ Is it safe to eat fish from Long Lake? (mercury & PFAS guide)

Long Lake fishing regulations (limits, seasons, special rules)

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

zebra mussel

Water Quality Trend: Stable

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.195 m/yr3
Phosphorus Declining+51 µg/L/yr2

Location

Loading map…

County Ranking

Ranked #19 of 35 lakes in Kandiyohi County

Cleaner Lakes Within 30 Miles

Long Lake holds Grade D. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Kandiyohi County

DNR Fisheries Survey Summary

18 surveys on file from MN DNR Fisheries. Most recent: 2025-04-23 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead52.220.58 lb
JND35.88
Walleye34.731.7 lb
Largemouth Bass23.172.35 lb
BLH19.72
Bluegill19.650.23 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.

Black Bullhead

12 fish · 615 in · 2025-04-23
4206789101112131415

Walleye

72 fish · 727 in · 2025-04-23
1470trophy 248101214161820222426

Largemouth Bass

121 fish · 418 in · 2021-06-03
371904681012141618

Bluegill

21 fish · 210 in · 2025-04-23
840trophy 102345678910

From the 2025-04-23 survey

A standard survey was conducted on Long Lake during late June of 2025. A targeted survey is generally used for sampling a specific kind of fish or time of year (i.e. spawning season, fall season, etc.) unlike a standard survey which samples a wider range of fish species during the summer months using standard…

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 Long Lake. 3 reports on file.

EPA Impairment Status

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

Causes of impairment

Impaired biota (cause unknown)MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN34-0192-00 · Official waterbody report

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: 2024-09-07

Monitoring stations: 2