Polk County Lake Quality
Minnesota, 21 lakes, average grade C (Fair)
Polk County's 21 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. Polk County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Union Lake (A) is the cleanest in the county.
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Quick Answers for Polk County
Planning a trip? Check special fishing regulations for Union Lake — or browse the full Minnesota regulations index.
Fishing in Polk County
DNR Reports (40)
Minnesota DNR LakeFinder resources for lakes in Polk County. browse all reports →
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — WhitefishFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — MoeFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — TurtleFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — StoreFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — SpringFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — SarahFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Sand HillFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — PoplarFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — MapleFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Hill RiverFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — CrossFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — CameronFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — CableFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — BadgerFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Badger (0104)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BadgerFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BadgerPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — CableFish Stocking History · MN DNR LakeFinder
- —Aquatic Plant Report — Cameron (0103)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — CameronFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CameronPublic Water Access Sites · MN DNR LakeFinder
- —Aquatic Plant Report — Cross (1958)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — CrossFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CrossPublic Water Access Sites · MN DNR LakeFinder
- —Aquatic Plant Report — Hill River (1956)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — Hill RiverPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — MapleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MaplePublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — PoplarFish Stocking History · MN DNR LakeFinder
- —Aquatic Plant Report — Sand Hill (0106)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — Sand HillPublic Water Access Sites · MN DNR LakeFinder
- —Aquatic Plant Report — Sarah (1955)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — SarahFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — SarahPublic Water Access Sites · MN DNR LakeFinder
- —Aquatic Plant Report — Spring (1952)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — SpringFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — SpringPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — StoreFish Stocking History · MN DNR LakeFinder
- —Aquatic Plant Report — Turtle (1959)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — TurtleFish Stocking History · MN DNR LakeFinder
All Lakes in Polk County
21 lakes · 19 graded, 2 not rated19 graded lakes · 2 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|---|
| 1 | AUnion LakePolk | A | 15 ft | 14 µg/L | 2.7 µg/L | No recent samples | No recent samples | ✓ Public |
| 2 | APoplar LakePolk | A | 8.9 ft | 23 µg/L | 3.6 µg/L | No recent samples | 23 ft | Carry-in |
| 3 | APerch LakePolk | A | 10.3 ft | 19.5 µg/L | 3.8 µg/L | No recent samples | 19 ft | Carry-in |
| 4 | ASpring LakePolk | A | 5.6 ft | 22.5 µg/L | 6.2 µg/L | No recent samples | 35 ft | ✓ Public |
| 5 | ACable LakePolk | A | 10.2 ft | 19 µg/L | 4.9 µg/L | No recent samples | 14 ft | ✓ Public |
| 6 | BBadger LakePolk | B | 6.6 ft | 27 µg/L | 7.5 µg/L | No recent samples | 19 ft | ✓ Public |
| 7 | BSarah LakePolk | B | 7.7 ft | 29.5 µg/L | 9.5 µg/L | No recent samples | 27 ft | ✓ Public |
| 8 | BKittleson LakePolk | B | 7.1 ft | 26 µg/L | 7.7 µg/L | No recent samples | No recent samples | Carry-in |
| 9 | CMaple LakePolk | C | 3.3 ft | 38.5 µg/L | 17.8 µg/L | No recent samples | 14 ft | ✓ Public |
| 10 | CSand Hill LakePolk | C | 6.9 ft | 26 µg/L | 6.8 µg/L | No recent samples | 17 ft | ✓ Public |
| 11 | DWhitefish LakePolk | D | 3.9 ft | 44 µg/L | 28.2 µg/L | No recent samples | 18 ft | ✓ Public |
| 12 | DTurtle LakePolk | D | 3 ft | 58.5 µg/L | 25.4 µg/L | No recent samples | 12 ft | ✓ Public |
| 13 | DCross LakePolk | D | 3 ft | 52 µg/L | 28.5 µg/L | No recent samples | 19 ft | ✓ Public |
| 14 | DHill River LakePolk | D | 4.1 ft | 73 µg/L | 29.2 µg/L | No recent samples | 60 ft | ✓ Public |
| 15 | DUff LakePolk | D | 3.9 ft | 35 µg/L | 20.5 µg/L | No recent samples | No recent samples | Carry-in |
| 16 | FUnnamed LakePolk | F | 2 ft | 72 µg/L | 51.4 µg/L | No recent samples | No recent samples | Carry-in |
| 17 | FOak LakePolk | F | 3 ft | 113 µg/L | 30.7 µg/L | No recent samples | No recent samples | Carry-in |
| 18 | FCameron LakePolk | F | 1 ft | 130 µg/L | 90.8 µg/L | No recent samples | 9 ft | ✓ Public |
| 19 | FStore LakePolk | F | 6.9 ft | 193 µg/L | 35 µg/L | No recent samples | 19 ft | Carry-in |
| NRUnnamed LakePolk | NR | 6.9 ft | 95 µg/L | 8.5 µg/L | No recent samples | 12 ft | Carry-in | |
| NRHalverson LakePolk | NR | 3 ft | 51 µg/L | 16.7 µg/L | No recent samples | No recent samples | Carry-in |
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.
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Other Counties in Minnesota
See how Polk 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.