Skip to main content
LakeQuality
C

Carlton County Lake Quality

Minnesota, 33 lakes, average grade C (Fair)

Carlton County's 33 graded lakes fall in the moderate-density bracket for Minnesota. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Big Lake (A); the most-stressed is Island Lake (D).

Loading map…

Where to stay near Carlton County

Top-rated places to stay near Carlton County

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 trip to Carlton County?

Get lake water-quality report cards plus the best cabin & lodging deals near Carlton County — straight to your inbox. No spam, unsubscribe anytime.

Quick Answers for Carlton County

Cleanest lakes in Carlton County →Cleanest lakes in Minnesota →Safest swimming lakes in Minnesota →

Planning a trip? Check special fishing regulations for Big Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Minnesota regulations index.

Fishing in Carlton County

Carlton County Fishing Guide

Fish species and best-graded lakes in Carlton County

DNR Reports (40)

Minnesota DNR LakeFinder resources for lakes in Carlton County. browse all reports →

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

All Lakes in Carlton County

33 lakes · 22 graded, 11 not rated22 graded lakes · 11 not rated, hidden

#LakeGradeClarityPhosphorusAlgaeTrophicMax DepthAccess
1ABig LakeCarltonA10 ft13.5 µg/L3.2 µg/LNo recent samples25 ft✓ Public
2AThird LakeCarltonA8.5 ft21.5 µg/L2.3 µg/LNo recent samplesNo recent samplesNot recorded
3APat Martin LakeCarltonA6.6 ft15 µg/L3.5 µg/LNo recent samplesNo recent samplesCarry-in
4APark LakeCarltonA7 ft14 µg/L3.1 µg/LNo recent samples16 ft✓ Public
5BEagle LakeCarltonB7 ft23.5 µg/L7.4 µg/LNo recent samples35 ft✓ Public
6CSand LakeCarltonC5 ft30 µg/L13.4 µg/LNo recent samples27 ft✓ Public
7CPerch LakeCarltonC2.2 ft51 µg/L6.1 µg/LNo recent samplesNo recent samples✓ Public
8CWild Rice LakeCarltonC3.2 ft200 µg/L2.8 µg/LNo recent samplesNo recent samplesNot recorded
9CHardwood LakeCarltonC5.1 ft200 µg/L5.1 µg/LNo recent samplesNo recent samplesNot recorded
10CSofie LakeCarltonC4.9 ft25 µg/L3.9 µg/LNo recent samplesNo recent samplesCarry-in
11CLac LakeCarltonC9.5 ft108 µg/L5.5 µg/LNo recent samplesNo recent samplesCarry-in
12CDeadfish LakeCarltonC1.6 ft63 µg/L3.6 µg/LNo recent samplesNo recent samplesCarry-in
13CRice Portage LakeCarltonC1.3 ft43 µg/L4.9 µg/LNo recent samplesNo recent samples✓ Public
14CHay LakeCarltonC6 ft24 µg/L10.7 µg/LNo recent samples14 ft✓ Public
15CKettle LakeCarltonCNo recent samples29 µg/LNo recent samplesNo recent samplesNo recent samples✓ Public
16DIsland LakeCarltonD5.1 ft26 µg/L14.7 µg/LNo recent samples22 ft✓ Public
17DCedar LakeCarltonD2 ft125 µg/L10 µg/LNo recent samplesNo recent samplesCarry-in
18DMiller LakeCarltonD1.8 ft57.5 µg/L9 µg/LNo recent samplesNo recent samples✓ Public
19DSpruce LakeCarltonD2.3 ft110 µg/L9.1 µg/LNo recent samplesNo recent samplesCarry-in
20DJaskari LakeCarltonD2.4 ft51 µg/L10.3 µg/LNo recent samplesNo recent samplesCarry-in
21DSecond LakeCarltonD1.2 ft75 µg/L13 µg/LNo recent samplesNo recent samples✓ Public
22DBang LakeCarltonD2 ft47 µg/L9.4 µg/LNo recent samples9 ftCarry-in
NREddy LakeCarltonNR3.5 ftNo recent samplesNo recent samplesNo recent samples37 ftCarry-in
NRTamarack LakeCarltonNR5 ftNo recent samplesNo recent samplesNo recent samples48 ft✓ Public
NRMoose LakeCarltonNR10.5 ftNo recent samplesNo recent samplesNo recent samples67 ftCarry-in
NREcho LakeCarltonNR11 ftNo recent samplesNo recent samplesNo recent samples47 ft✓ Public
NRMoosehead LakeCarltonNR4 ftNo recent samplesNo recent samplesNo recent samples18 ft✓ Public
NRCole LakeCarltonNR10 ftNo recent samplesNo recent samplesNo recent samples24 ft✓ Public
NRChub LakeCarltonNR13.7 ftNo recent samplesNo recent samplesNo recent samples28 ft✓ Public
NRHanging Horn LakeCarltonNR6.5 ftNo recent samplesNo recent samplesNo recent samples80 ft✓ Public
NRLittle Hanging Horn LakeCarltonNR11.5 ftNo recent samplesNo recent samplesNo recent samples31 ft✓ Public
NRThomson ReservoirCarltonNR4 ftNo recent samplesNo recent samplesNo recent samples22 ftCarry-in
NRLittle Kettle LakeCarltonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded

NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

Lake Match

Which lake suits how you actually use one?

Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.

Take the quiz →

Other Counties in Minnesota

Clay County

2 lakes · Avg grade A

Morrison County

16 lakes · Avg grade A

Hubbard County

76 lakes · Avg grade A

Cass County

130 lakes · Avg grade A

Cook County

139 lakes · Avg grade A

Crow Wing County

121 lakes · Avg grade A

See how Carlton County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.

Source: EPA National Aquatic Resource Surveys, 2026.