Tyson Lake
Tyson Lake in Yellow Medicine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.5 ft visibility. Maximum depth: 8 ft. Surface area: 165.85 acres.
- Clarity
- 4.5 ft
- Max depth
- 8 ft
- Area
- 166 acres
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Yellow Medicine County
Why Tyson 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 Tyson 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.
Tyson Lake is a 166-acre lake in Yellow Medicine County, Minnesota with a maximum depth of 8 feet. Overall water quality is declining over recent sampling years. The lake supports 8 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-08-13. 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 Tyson Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 4.5 ft. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Tyson Lake
Compare lakeside cabins, hotels, and vacation rentals near Tyson Lake in Yellow Medicine 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 Tyson Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 8 ft |
| Surface Area | 166 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Tyson LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Tyson Lake
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2023-09-13 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 150.80 | 0.22 lb |
| Walleye | 48.29 | 1.33 lb |
| Yellow Perch | 10.61 | 0.33 lb |
| OSS | 7.09 | 0.03 lb |
| Bluegill | 7.08 | 0.32 lb |
| Hybrid Sunfish | 3.22 | 0.17 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.
Black Bullhead
Walleye
Yellow Perch
OSS
From the 2023-09-13 survey
A targeted fall night electrofishing survey was conducted on Tyson during September 13, 2023 to evaluate young of year "YOY" (fingerling sized) Walleye numbers due to fry stocking/natural reproduction. One station was sampled for 10 minutes at dusk. The water temperature was 70 F. Water clarity was poor (6 inches)…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Tyson Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — TysonFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — TysonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — TysonPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.275 m/yr | 5 |
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Tyson Lake under Clean Water Act (NPDES) discharge permits.
- Nsp-Minnesota Valley PlantGranite Falls · 1.3 mi away · NPDES MN0000906
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 Tyson Lake
Tyson Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Yellow Medicine County
Frequently asked questions about Tyson Lake
What is the water quality grade for Tyson Lake?
- Tyson Lake in Yellow Medicine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.5 ft visibility. Maximum depth: 8 ft. Surface area: 165.85 acres.
Is Tyson Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Tyson 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 Tyson Lake?
- Tyson Lake has a maximum depth of 8 feet. The lake covers 165.85 acres.
What fish are in Tyson Lake?
- Fish species found in Tyson Lake include black bullhead, black crappie, bluegill, green sunfish, hybrid sunfish, orangespotted sunfish, walleye, yellow perch. Tyson Lake is located in Yellow Medicine County, Minnesota.
Are there boat ramps on Tyson Lake?
- Tyson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Tyson Lake. Public access is listed as yes.
Explore Tyson Lake across LakeGrade
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Where this data comes from
29 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA29 samples · 2020–2024
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