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C

Sibley Lake

Crow Wing County, MinnesotaEutrophic

The LakeGrade rubric puts Sibley Lake at a C: clarity at 4.9 ft, 26 µg/L of phosphorus, and a TSI of 53 signal an intermediate trophic state. Secchi readings are the weakest of the scored parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Sibley Lake reaches 40 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 444 acres, Sibley Lake fits the Minnesota median for monitored lakes, with 9.1 miles of shoreline. Within the 120 graded lakes of Crow Wing County, Sibley Lake sits at rank 109, near the bottom of the county list.

Sibley Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Sibley Lake, one of 16 fish species on record for the lake. A documented public access point at Sibley Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a partial ice record — 10 observed ice-outs, centered near Apr 17. 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 2024-10-13. 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 4.9 ft. Phosphorus level: 26 µg/L. Trophic State Index: 53.

MetricValueGrade
Water Clarity (Secchi Depth)4.9 ftD
Phosphorus26 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)53Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth40 ft
Surface Area444.24 acres
Shoreline Length9.1 mi
Littoral Zone57%
Public AccessYes

Fish Species

black bullhead,black crappie,bluegill,bowfin (dogfish),brown bullhead,common carp,green sunfish,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,rock 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 Sibley Lake (14-day solunar calendar)

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

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

Water Quality Trend: Stable

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

MetricTrendChange/YearYears
Water Clarity Improving+0.1 m/yr5
Phosphorus Declining+0.8 µg/L/yr5
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (19 observations).

Typical Ice-Out
Apr 17
Typical Ice-In
Nov 20

Estimated open water season: 217 days

EarliestLatest
Ice-Out2024-03-12 (2024)2013-05-09 (2013)
Ice-In2019-11-06 (2019)2024-11-30 (2024)

Most recent ice-out: 2024-03-12

Location

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County Ranking

Ranked #109 of 120 lakes in Crow Wing County

Cleaner Lakes Within 30 Miles

Sibley Lake holds Grade C. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Crow Wing County

DNR Fisheries Survey Summary

8 surveys on file from MN DNR Fisheries. Most recent: 2021-08-05 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
White Sucker33.641.99 lb
Bluegill26.340.14 lb
CNM24.64
JND17.04
CSH14.000.1 lb
BNS11.57

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.

White Sucker

2 fish · 1720 in · 2021-08-05
1017181920

Bluegill

210 fish · 37 in · 2021-08-05
6432034567

From the 2021-08-05 survey

A targeted survey of nearshore fish species in Sibley Lake was conducted on August 5, 2021, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack…

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 Sibley Lake. 3 reports on file.

Reservoir Info (USACE NID)

Sibley Lake is a man-made reservoir impounded by the Sibley Lake (completed 1937), built primarily for recreation on the MAYO CREEK - TR; gravity-type dam, 8 ft tall and 41 ft long.

Surface area
418 ac
Normal storage
10,200 ac-ft
Max storage
11,730 ac-ft
Drainage area
55 sq mi
Hazard class
Undetermined
Owner
MNDNR

Source: USACE National Inventory of Dams, NID ID MN00045 · Operator website

EPA Impairment Status

Sibley 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 MN18-0404-00 · 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: 2024-10-13

Monitoring stations: 3