Swamp Lake
Swamp Lake in Unknown County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.2 ft visibility. Maximum depth: 50 ft. Surface area: 108.63 acres.
Minnesota DNR surveys at Swamp Lake average 9.50 northern pike per unit of sampling effort (CPUE) across 3 surveys. The most recent is a Targeted Survey dated July 31, 2025. DNR survey details →
- Clarity
- 16.2 ft
- Max depth
- 50 ft
- Area
- 109 acres
- Trend
- → Stable
- Public access
- No
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Why Swamp Lake has no grade
We grade a lake only when the monitoring record supports a letter: 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 Swamp Lake, no EPA ecoregion for this lake, so the National Lakes Assessment condition thresholds cannot be applied. 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.
Swamp Lake is a 109-acre lake in Unknown County, Minnesota with a maximum depth of 50 feet. 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 2022-06-21. Grade methodology: LakeQuality 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 Swamp Lake
These readings exist but are not enough for an A–F grade — see why.
Crystal clear, you can see 16.2 ft down. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Swamp Lake
Compare lakeside cabins, hotels, and vacation rentals near Swamp Lake in Unknown 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 Swamp Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Minnesota DNR surveys at Swamp Lake average 9.50 northern pike per unit of sampling effort (CPUE) across 3 surveys. The most recent is a Targeted Survey dated July 31, 2025.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Swamp Lake — official chemistry is on file, not a letter, and the water-quality trend over 2 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 2025-07-31 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Tullibee (Cisco) | 13.50 | 1.3 lb |
| Northern Pike | 9.50 | 2.39 lb |
| Rock Bass | 3.25 | 0.22 lb |
| White Sucker | 3.25 | 1.78 lb |
| Largemouth Bass | 0.50 | 1.8 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE means more abundant in standardized sampling. This is not a weekly bite report.
From the 2025-07-31 survey
Temperature and dissolved oxygen measurements were collected from the deepest basin in Ashdick Lake on July 31st, 2025. This was done 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…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Swamp Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — AshdickFisheries Lake Survey · MN DNR LakeFinder
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 50 ft |
| Surface Area | 109 acres |
| Shoreline Length | 3.9 mi |
| Littoral Zone | 58% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Swamp Lake
Water Quality Trend: → Stable
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.05 m/yr | 2 |
Nearby Lakes in Unknown County
Frequently asked questions about Swamp Lake
Where is Swamp Lake?
- Swamp Lake is a lake in Unknown County, Minnesota. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Swamp Lake?
- Swamp Lake in Unknown County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.2 ft visibility. Maximum depth: 50 ft. Surface area: 108.63 acres.
Is Swamp Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Swamp 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 Swamp Lake?
- Swamp Lake has a maximum depth of 50 feet. The lake covers 108.63 acres.
What did the DNR fisheries survey find at Swamp Lake?
- Minnesota DNR surveys at Swamp Lake average 9.50 northern pike per unit of sampling effort (CPUE) across 3 surveys. The most recent is a Targeted Survey dated July 31, 2025. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Swamp Lake — official chemistry is on file, not a letter, and the water-quality trend over 2 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
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Where this data comes from
2 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
MNPCA2 samples · 2020–2022
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder