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LakeQuality

Bonnie Lake

NR
Not yet rated
17 ft clear · Oligotrophic · 76 acres
Limited DataOligotrophic

Bonnie Lake in Crow Wing County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 17 ft visibility. Maximum depth: 42 ft. Surface area: 76.11 acres.

Clarity
17 ft
Max depth
42 ft
Area
76 acres
Trend
Improving
Public access
No
Ice-out
Apr 10
Open water
220 days

Next lake in Crow Wing County

ABass Lake13 ft clear · Crow Wing CountyView →
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Why Bonnie Lake has no grade

We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Bonnie Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Bonnie Lake is a 76-acre lake in Crow Wing County, Minnesota with a maximum depth of 42 feet. Overall water quality is improving over recent sampling years. The lake supports 7 documented fish species including bluegill, hybrid sunfish, and largemouth bass. No public access — the lake is private or restricted.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-02. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Brainerd

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Water quality measurements for Bonnie Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Crystal clear, you can see 17 ft down. Trophic State Index: 36.

MetricValueGrade
Water Clarity (Secchi Depth)17 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)36Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near Bonnie Lake

Compare lakeside cabins, hotels, and vacation rentals near Bonnie Lake in Crow Wing County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

Top-rated places to stay near Bonnie Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Lake Details

CharacteristicValue
Maximum Depth42 ft
Surface Area76 acres
Shoreline Length1.4 mi
Littoral Zone51%
Public AccessNo

Lake Size & Watershed

Watershed (drainage) area
1 sq mi
Elevation
1,201 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Bonnie Lake

DNR Fisheries Survey Summary

2 surveys on file from MN DNR Fisheries. Most recent: 2021-09-27 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Yellow Bass22.080.71 lb
Bluegill14.250.16 lb
Northern Pike6.674.21 lb
Hybrid Sunfish4.130.23 lb
Yellow Perch2.000.1 lb
Brown Bullhead2.001.61 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.

Yellow Bass

19 fish · 711 in · 2021-09-27
8407891011

Bluegill

13 fish · 38 in · 2021-09-27
950345678

Northern Pike

1 fish · 3030 in · 2021-09-27
1030

Hybrid Sunfish

8 fish · 27 in · 2021-09-27
320234567

From the 2021-09-27 survey

Bonnie is a 76 acre lake in the center of Crow Wing County with a maximum depth of 42 feet and no public access. Two single frame 3/8" trap nets were walked out from shore on September 27, 2021 and left overnight to get a sample of the species found in the lake. Seven species were captured, with Yellow Bullhead…

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 Bonnie Lake. 2 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.141 m/yr6
Phosphorus Stable-0.31 µg/L/yr6
Chlorophyll-a Improving-0.2 µg/L/yr6
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (14 observations).

Typical Ice-Out
Apr 10
Typical Ice-In
Nov 16

Estimated open water season: 220 days

EarliestLatest
Ice-Out2007-04-05 (2007)2008-04-24 (2008)
Ice-In2017-11-05 (2017)2006-12-02 (2006)

Most recent ice-out: 2015-04-07

Graded lakes near Bonnie Lake

Bonnie Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Crow Wing County

Frequently asked questions about Bonnie Lake

What is the water quality grade for Bonnie Lake?

Bonnie Lake in Crow Wing County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 17 ft visibility. Maximum depth: 42 ft. Surface area: 76.11 acres.

Is Bonnie Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Bonnie Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

How deep is Bonnie Lake?

Bonnie Lake has a maximum depth of 42 feet. The lake covers 76.11 acres.

What fish are in Bonnie Lake?

Fish species found in Bonnie Lake include bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, yellow bullhead, yellow perch. Bonnie Lake is located in Crow Wing County, Minnesota.

When does Bonnie Lake thaw?

Bonnie Lake typically has ice-out around Apr 10. Ice typically forms around Nov 16. The open water season is approximately 220 days.

Oligotrophic Lakes in Minnesota

Where this data comes from

16 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA16 samples · 2020–2024

Analytical methods

  • Field measurement/observation, generic method
Monitoring station identifiers (2)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder

Ice data from Minnesota DNR Climate