Ml-Peterson Lake
Mille Lacs County, MinnesotaMesotrophic
Ml-Peterson Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.
The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. Ml-Peterson Lake reaches 42 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 128,250 acres, Ml-Peterson Lake is one of the larger lakes in Mille Lacs County, with 105.5 miles of shoreline supporting multiple distinct use patterns. Ml-Peterson Lake ranks 5 of 11 in Mille Lacs County — solidly in the upper half of the local distribution.
Zebra mussel presence at Ml-Peterson Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Muskie are on the species list at Ml-Peterson Lake, among the lake's 21 documented fish. A documented public access point at Ml-Peterson Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been logged at Ml-Peterson Lake more than two dozen times, putting the median around Apr 25 — a useful baseline for tracking climate trends. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-08. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 7.4 ft. Phosphorus level: 26.5 µg/L. Chlorophyll-a: 3.9 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.4 ft | C |
| Phosphorus | 26.5 µg/L | B |
| Chlorophyll-a (Algae) | 3.9 µg/L | A |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 42 ft |
| Average Depth | 28.5 ft |
| Surface Area | 128.3K acres |
| Shoreline Length | 105.5 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Ml-Peterson Lake (14-day solunar calendar)
→ Is it safe to eat fish from Ml-Peterson Lake? (mercury & PFAS guide)
→ Ml-Peterson 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.
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +4.96 m/yr | 2 |
| Phosphorus | ↓ Declining | +55.6 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -1.39 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (123 observations).
Estimated open water season: 222 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-16 (2024) | 2013-05-16 (2013) |
| Ice-In | 1996-11-19 (1996) | 2001-12-22 (2001) |
Most recent ice-out: 2025-04-18
Location
County Ranking
Ranked #5 of 11 lakes in Mille Lacs County
Nearby Lakes in Mille Lacs County
More Minnesota Lake Rankings
State Parks Near Ml-Peterson Lake
Other Grade B Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Ml-Peterson Lake With Nearby Lakes
Mille Lacs County · Grade C
Mille Lacs County · Grade B
Aitkin County · Grade B
Aitkin County · Grade C
Mille Lacs County · Grade B
Mille Lacs County · Grade B
DNR Fisheries Survey Summary
36 surveys on file from MN DNR Fisheries. Most recent: 2024-09-01 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 219.50 | 0.23 lb |
| Spottail Shiner | 73.62 | 0.02 lb |
| Walleye | 69.99 | 1.23 lb |
| Tullibee (Cisco) | 17.45 | 0.62 lb |
| Smallmouth Bass | 16.43 | 1.74 lb |
| Bluntnose Minnow | 13.53 | 0.01 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 Perch
Spottail Shiner
Walleye
Tullibee (Cisco)
From the 2024-09-01 survey
Sampling Programs Mille Lacs Lake is one of ten lakes in Minnesota's Large Lake Program. These lakes have annual sampling of the fish populations, and frequent creel surveys. Specific to Mille Lacs Lake, sampling programs focusing on Walleye, Yellow Perch, Smallmouth Bass, and Northern Pike are conducted annually.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ml-Peterson Lake. 5 reports on file.
- —Fisheries Lake Survey — Mille LacsFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Mille Lacs (0134)Aquatic Plant Report · MN DNR LakeFinder
- —Aquatic Plant Report — Mille Lacs (0337)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Mille LacsFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Mille LacsPublic Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2024-10-08
Monitoring stations: 1