Hay Lake
Hay Lake in Carlton County, Minnesota has a water quality grade of C (Fair). Water clarity: 6 ft visibility. Phosphorus: 24 µg/L. Chlorophyll-a (algae): 10.7 µg/L. Maximum depth: 14 ft. Surface area: 140.05 acres.
- Clarity
- 6 ft
- Typical in August
- 71°F
- Max depth
- 14 ft
- Area
- 140 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 10
Next lake in Carlton County
Hay Lake is a 140-acre productive, nutrient-rich eutrophic lake in Carlton County, Minnesota with a maximum depth of 14 feet (4-foot average). Water quality is graded C based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 10 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 21 other monitored lakes in Carlton County, Hay Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-18. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 6 ft. Phosphorus level: 24 µg/L. Chlorophyll-a: 10.7 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | Not graded |
| Phosphorus | 24 µg/L | Good |
| Chlorophyll-a (Algae) | 10.7 µg/L | Fair |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Hay Lake
Compare lakeside cabins, hotels, and vacation rentals near Hay Lake in Carlton 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.
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Water Temperature
Hay Lake typically sits around 71°F at the surface in August. Summer average is about 68°F. Usually warmest in Aug (about 71°F) and coldest in May (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 76 field readings (2010–2023) via the EPA Water Quality Portal. See the full Hay Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 14 ft |
| Average Depth | 3.9 ft |
| Surface Area | 140 acres |
| Shoreline Length | 4.5 mi |
| Littoral Zone | 87% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Hay LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Hay Lake
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 2021-08-16 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 11.01 | 0.19 lb |
| Brown Bullhead | 9.86 | 1.17 lb |
| Black Bullhead | 8.95 | 0.98 lb |
| Northern Pike | 3.73 | 1.92 lb |
| White Sucker | 2.51 | 4.16 lb |
| Bluegill | 1.74 | 0.29 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.
Yellow Perch
Brown Bullhead
Black Bullhead
Northern Pike
From the 2021-08-16 survey
Hay Lake is a 215 acre lake with 214 acres (99.5%) of littoral area and a maximum depth of 16 feet. The lake is located southwest of Wrenshall, MN off of County Road 4. It has a county-owned earthen access located at the southern end of the lake. The current fisheries management plan for Hay directs Walleye fry…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Hay Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — HayFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Hay (0259)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — HayFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — HayPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.07 m/yr | 2 |
| Phosphorus | ↓ Declining | +3 µg/L/yr | 2 |
| Chlorophyll-a | → Stable | +0.2 µg/L/yr | 2 |
Ice Season
Historical ice data from Minnesota DNR (8 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 1998-04-05 (1998) | 2014-05-06 (2014) |
| Ice-In | 2010-11-20 (2010) | 2010-11-20 (2010) |
Most recent ice-out: 2023-05-01
EPA Impairment Status
Hay Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN09-0008-00 · Official waterbody report · Matched by proximity (2.82 km)
County Ranking
Ranked #14 of 22 lakes in Carlton County
Nearby Lakes With Higher Grades
Hay Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Carlton County
Frequently asked questions about Hay Lake
What is the water quality grade for Hay Lake?
- Hay Lake in Carlton County, Minnesota has a water quality grade of C (Fair). Water clarity: 6 ft visibility. Phosphorus: 24 µg/L. Chlorophyll-a (algae): 10.7 µg/L. Maximum depth: 14 ft. Surface area: 140.05 acres.
Is Hay Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Hay Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 10.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Hay Lake?
- Hay Lake typically sits around 71°F at the surface in August, from 76 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Hay Lake?
- Hay Lake has a maximum depth of 14 feet and an average depth of 3.9 feet. The lake covers 140.05 acres.
What fish are in Hay Lake?
- Fish species found in Hay Lake include black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Hay Lake is located in Carlton County, Minnesota.
When does Hay Lake thaw?
- Hay Lake typically has ice-out around Apr 10.
Are there boat ramps on Hay Lake?
- Hay Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Hay Lake. Public access is listed as yes.
Explore Hay Lake across LakeGrade
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High nutrients, frequent algae, reduced clarity
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Where this data comes from
36 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA36 samples · 2022–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- 2120 B ~ Color in Water by Visual Comparison
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
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