Mille Lacs Lake
Mille Lacs Lake in Mille Lacs County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 42 ft. Surface area: 128250.02 acres.
- Clarity
- 9 ft
- Typical in August
- 78°F
- Max depth
- 42 ft
- Area
- 128,250 acres
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 25
- Open water
- 222 days
Next lake in Mille Lacs County
Why Mille Lacs 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 Mille Lacs 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.
Mille Lacs Lake is a 128,250-acre lake in Mille Lacs County, Minnesota with a maximum depth of 42 feet (29-foot average). Overall water quality is improving over recent sampling years. The lake supports 21 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 6 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Mille Lacs Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 9 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mille Lacs Lake
Compare lakeside cabins, hotels, and vacation rentals near Mille Lacs Lake in Mille Lacs 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 Mille Lacs Lake
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Water Temperature
Mille Lacs Lake typically sits around 78°F at the surface in August. Summer average is about 72°F. Usually warmest in Aug (about 78°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2022–2025) via the EPA Water Quality Portal. See the full Mille Lacs Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Mille Lacs Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (71,779 cells/mL) on November 29, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 42 ft |
| Average Depth | 28.5 ft |
| Surface Area | 128,250 acres |
| Shoreline Length | 105.5 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Wahkon ParkPublic
- Father Hennepin State Park (West)Public
- Father Hennepin State Park (East)Public
- 4th Street WestPublic
- Frederickson MarinaSemi-private
- Mille Lacs AvenueSemi-private
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mille Lacs Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
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 Mille Lacs Lake. 5 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —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
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.102 m/yr | 6 |
| Phosphorus | → Stable | +0.31 µg/L/yr | 5 |
| Chlorophyll-a | ↑ Improving | -0.4 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
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Mille Lacs Lake under Clean Water Act (NPDES) discharge permits.
- Mdnr Father Hennepin State ParkIsle · 0.6 mi away · NPDES MN0033723
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near Mille Lacs Lake
Mille Lacs Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Mille Lacs County
Frequently asked questions about Mille Lacs Lake
What is the water quality grade for Mille Lacs Lake?
- Mille Lacs Lake in Mille Lacs County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 42 ft. Surface area: 128250.02 acres.
Is Mille Lacs Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Mille Lacs Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Mille Lacs Lake?
- Mille Lacs Lake typically sits around 78°F at the surface in August, from 29 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Mille Lacs Lake?
- Mille Lacs Lake has a maximum depth of 42 feet and an average depth of 28.5 feet. The lake covers 128250.02 acres.
What fish are in Mille Lacs Lake?
- Fish species found in Mille Lacs Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, burbot, common carp, green sunfish, hybrid sunfish, largemouth bass, muskellunge, northern pike, pumpkinseed, rock bass, shorthead redhorse, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Mille Lacs Lake is located in Mille Lacs County, Minnesota.
When does Mille Lacs Lake thaw?
- Mille Lacs Lake typically has ice-out around Apr 25. Ice typically forms around Dec 3. The open water season is approximately 222 days.
Does Mille Lacs Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Mille Lacs Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (71,779 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Mille Lacs Lake?
- Mille Lacs Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Wahkon Park, Father Hennepin State Park (West), Father Hennepin State Park (East), 4th Street West, among others. Public access is listed as yes.
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Where this data comes from
55 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA55 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (1)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate