Mill Lake
Douglas County, Minnesota451 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Mill Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- zebra mussel
- 40 ft max depth
- Public access
- Limited data
Mill Lake in Douglas County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 9 µg/L. Maximum depth: 40 ft. Surface area: 451.12 acres.
Minnesota DNR's Standard Survey on June 11, 2024 caught 2.78 walleye per gill net at Mill Lake. DNR survey details →
Mill Lake is a 451-acre mesotrophic lake in Douglas County, Minnesota with a maximum depth of 40 feet (20-foot average). Overall water quality is declining over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Douglas County, Mill Lake ranks #27 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-14. Methodology: how these readings are compared.
Mill Lake covers about 450 acres in Douglas County. It has one public boat landing. The median ice-out date is April 11, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around Mill Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Mill Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11 ft of visibility
- Boat launch1 documented ramp
- Fishing15 species recorded
- Ice seasonIce-out around Apr 11
- Deep water40 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Mill Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Mill Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mill Lake
These are the measurements Minnesota PCA publishes for Mill Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11 ft. Phosphorus 23 µg/L. Chlorophyll-a 9 µg/L. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 23µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 9µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Mill Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Mill Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (6,668 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 ↗
Minnesota DNR's Standard Survey on June 11, 2024 caught 2.78 walleye per gill net at Mill Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mill Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2024-06-11 (Standard Survey).
13 surveys on file · most recent 2024-06-11 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluntnose Minnow | 45.60 | ||
| Bluegill | 19.00 | 4–9 in 2024-06-11 | 0.23 lb |
| Largemouth Bass | 17.63 | 6–18 in 2024-06-11 | 0.87 lb |
| Yellow Perch | 15.69 | 5 in 2024-06-11 | 0.12 lb |
| Yellow Bullhead | 13.87 | 9–13 in 2024-06-11 | 0.66 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Bluegill
Largemouth Bass
Yellow Perch
Yellow Bullhead
From the 2024-06-11 survey
Mill Lake is a 461-acre, moderately productive basin located eight miles southwest of Alexandria. Maximum depth of the lake is 40.0 feet. Average depth is estimated at 20.0 feet. Water clarity has increased markedly in response to establishment of zebra mussels. Water transparency at time of the June 2024 survey was…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mill Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MillFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Mill (0929)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — MillFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MillPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
40 ft
Average depth
20 ft
Surface area
451 acres
Shoreline
5.4 mi
Littoral zone
44%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
27 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,358 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Mill LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Mill Lake
Compare lakeside cabins, hotels, and vacation rentals near Mill Lake in Douglas 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 Mill Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
Follow Mill Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Mill 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.
Water quality readings over time
3 seasons of samples on record (2020–2022). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening3 years
Ice season
Typical ice-out
Apr 11
Earliest Mar 21, 2016 · Latest Apr 25, 2022
Typical ice-in
Dec 8
Earliest Nov 13, 2018 · Latest Dec 26, 2001
Most recent ice-out
Apr 25
2022
11 observations · Minnesota PCA ice records
EPA Impairment Status
Mill Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MN21-0180-00 · Official waterbody report
Nearby Lakes in Douglas County
Frequently asked questions about Mill Lake
Where is Mill Lake?
- Mill Lake is a lake in Douglas County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Mill Lake?
- Mill Lake in Douglas County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 9 µg/L. Maximum depth: 40 ft. Surface area: 451.12 acres.
Is Mill Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mill Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Mill Lake?
- Mill Lake has a maximum depth of 40 feet and an average depth of 20 feet. The lake covers 451.12 acres.
What fish are in Mill Lake?
- Fish species found in Mill Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Mill Lake is located in Douglas County, Minnesota.
What did the DNR fisheries survey find at Mill Lake?
- Minnesota DNR's Standard Survey on June 11, 2024 caught 2.78 walleye per gill net at Mill Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mill Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
When does Mill Lake thaw?
- Mill Lake typically has ice-out around Apr 11. Ice typically forms around Dec 8. The open water season is approximately 241 days.
Does Mill Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Mill Lake (clouds, ice, or an off-season gap). The most recent reading was low (6,668 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Mill Lake?
- Mill Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mill Lake. Public access is listed as yes.
Can I fish at Mill Lake?
- Mill Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Mill Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Douglas County
Species activity outlook by water temperature and season
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Where to stay at Minnesota's top lakes, each with its readings
Lakes in the St. Croix Watershed, ranked by water quality
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
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Minnesota's cleanest lakes, ranked on agency measurements
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Where this data comes from
46 measurements from 2 monitoring stations, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA46 samples · 2020–2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
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