Ash Lake
St. Louis County, Minnesota690 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Ash Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- 25 ft max depth
- Public access
- Limited data
Ash Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.5 ft visibility. Phosphorus: 39 µg/L. Chlorophyll-a (algae): 11.1 µg/L. Maximum depth: 25 ft. Surface area: 689.62 acres.
Ash Lake is a 690-acre productive, nutrient-rich eutrophic lake in St. Louis County, Minnesota with a maximum depth of 25 feet. The lake supports 9 documented fish species including black crappie, bluegill, and hybrid sunfish. Public access is available with 1 public boat landing. Compared to the 67 other monitored lakes in St. Louis County, Ash Lake ranks #60 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. Methodology: how these readings are compared.
Ash Lake covers about 690 acres in St. Louis County. It has one public boat landing. The median ice-out date is April 25, which is when the open-water season begins. Vrbo is where to look for cabins and lake homes around Ash Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Ash Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing9 species recorded
- Ice seasonIce-out around Apr 25
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. Ash Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Ash 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 Ash Lake
These are the measurements Minnesota PCA publishes for Ash Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.5 ft. Phosphorus 39 µg/L. Chlorophyll-a 11.1 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 39µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 11.1µg/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. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Ash Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Ash Lake typically sits around 65°F at the surface in September. Summer average is about 68°F. Usually warmest in Aug (about 70°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (57°F) to its warmest (70°F).
Typical surface water temperature by month, from 63 field readings (2011–2025) via the EPA Water Quality Portal. See the full Ash Lake water temperature breakdown →
Lake Details
Max depth
25 ft
Surface area
690 acres
Shoreline
6 mi
Littoral zone
28%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
10 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,289 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ash 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 Ash Lake
Compare lakeside cabins, hotels, and vacation rentals near Ash Lake in St. Louis 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 Ash 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 Ash Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Ash Lake
Ice season
Typical ice-out
Apr 25
Earliest Mar 26, 2012 · Latest May 9, 2014
Most recent ice-out
Apr 28
2020
7 observations · Minnesota PCA ice records
EPA Impairment Status
Ash Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN69-0864-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Ash Lake
Where is Ash Lake?
- Ash Lake is a lake in St. Louis County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Ash Lake?
- Ash Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.5 ft visibility. Phosphorus: 39 µg/L. Chlorophyll-a (algae): 11.1 µg/L. Maximum depth: 25 ft. Surface area: 689.62 acres.
Is Ash Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Ash Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Ash Lake?
- Ash Lake typically sits around 65°F at the surface in September, from 63 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Ash Lake?
- Ash Lake has a maximum depth of 25 feet. The lake covers 689.62 acres.
What fish are in Ash Lake?
- Fish species found in Ash Lake include black crappie, bluegill, hybrid sunfish, northern pike, pumpkinseed, smallmouth bass, walleye, white sucker, yellow perch. Ash Lake is located in St. Louis County, Minnesota.
When does Ash Lake thaw?
- Ash Lake typically has ice-out around Apr 25.
Are there boat ramps on Ash Lake?
- Ash Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ash Lake. Public access is listed as yes.
Can I fish at Ash Lake?
- Ash 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 Ash Lake across LakeQuality
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Where this data comes from
20 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA20 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
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