Ashigan Lake
Ashigan Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 12.2 ft visibility. Maximum depth: 59 ft. Surface area: 153.33 acres.
- Clarity
- 12.2 ft
- Max depth
- 59 ft
- Area
- 153 acres
- Trend
- ↑ Improving
- Public access
- No
Next lake in Lake County
Why Ashigan 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 Ashigan 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.
Ashigan Lake is a 153-acre lake in Lake County, Minnesota with a maximum depth of 59 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-10. Grade methodology: LakeGrade methodology.
Watch Ashigan Lake water quality
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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 Ashigan Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 12.2 ft. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Ashigan Lake
Compare lakeside cabins, hotels, and vacation rentals near Ashigan Lake in Lake 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 Ashigan Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 59 ft |
| Surface Area | 153 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 6% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Ashigan Lake
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 2025-08-19 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Smallmouth Bass | 10.33 | 0.35 lb |
| Tullibee (Cisco) | 6.00 | 0.33 lb |
| Yellow Perch | 3.33 | 0.28 lb |
| White Sucker | 2.33 | 2.79 lb |
| Green Sunfish | 1.33 | 0.1 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 2025-08-19 survey
Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Ashigan Lake on August 19th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ashigan Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — AshiganFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.102 m/yr | 5 |
EPA Impairment Status
Ashigan Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN38-0498-00 · Official waterbody report · Matched by proximity (2.99 km)
Nearby Lakes in Lake County
Frequently asked questions about Ashigan Lake
What is the water quality grade for Ashigan Lake?
- Ashigan Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 12.2 ft visibility. Maximum depth: 59 ft. Surface area: 153.33 acres.
Is Ashigan Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Ashigan Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Ashigan Lake?
- Ashigan Lake has a maximum depth of 59 feet. The lake covers 153.33 acres.
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Where this data comes from
27 measurements from 8 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA27 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (8)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder