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C

Locke Lake

Wright County, MinnesotaEutrophic

Locke Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. A maximum depth of 49 ft puts Locke Lake in the middle of Minnesota's depth distribution. The lake's 140 acres and 2.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Wright County's 64 graded lakes, Locke Lake ranks 33 — below the local median, though not at the bottom.

Zebra mussels have been documented at Locke Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Locke Lake, one of 15 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Locke Lake more than two dozen times, putting the median around Apr 8 — 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 2024-09-15. 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

Murky, only visible to about 4.3 ft. Phosphorus level: 32 µg/L. Trophic State Index: 55.

MetricValueGrade
Water Clarity (Secchi Depth)4.3 ftD
Phosphorus32 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)55Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth49 ft
Average Depth18.1 ft
Surface Area139.97 acres
Shoreline Length2.6 mi
Littoral Zone48%
Public AccessYes

Fish Species

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

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

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

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

Locke 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.

Eurasian watermilfoilzebra mussel

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.055 m/yr5
Phosphorus Declining+6.9 µg/L/yr5
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (48 observations).

Typical Ice-Out
Apr 8
Typical Ice-In
Dec 8

Estimated open water season: 244 days

EarliestLatest
Ice-Out2024-03-07 (2024)2018-05-01 (2018)
Ice-In2014-11-15 (2014)2024-01-11 (2024)

Most recent ice-out: 2024-03-07

Location

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County Ranking

Ranked #33 of 64 lakes in Wright County

Cleaner Lakes Within 30 Miles

Locke Lake holds Grade C. 4 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Wright County

DNR Fisheries Survey Summary

14 surveys on file from MN DNR Fisheries. Most recent: 2025-10-08 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
BKS104.25
Black Bullhead41.510.43 lb
Bluegill20.040.23 lb
Walleye16.111.36 lb
Smallmouth Bass12.221.33 lb
Largemouth Bass11.141.94 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.

BKS

24 fish · 12 in · 2008-06-16
2312012

Black Bullhead

8 fish · 713 in · 2016-06-13
32078910111213

Bluegill

25 fish · 57 in · 2021-06-21
19100567

Walleye

33 fish · 816 in · 2025-10-08
12608910111213141516

From the 2025-10-08 survey

Locke Lake is a 156-acre general development lake located one mile southeast of Hasty in northern Wright County. The watershed is large (32,365 acres) and the primary land uses are cultivated crops (43%), forest (16%), and hay/pasture (11%). A downstream barrier on Silver Creek isolates Locke Lake from the Mississippi…

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 Locke Lake. 3 reports on file.

EPA Impairment Status

Locke 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)Nutrients (phosphorus, nitrogen)

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

Source: EPA ATTAINS assessment unit MN86-0168-00 · 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

Ice data from Minnesota DNR Climate

Most recent sample: 2024-09-15

Monitoring stations: 1