Sweeney Lake
Sweeney Lake in Hennepin County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.9 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 28 ft. Surface area: 67.64 acres.
- Clarity
- 6.9 ft
- Typical in August
- 71°F
- Max depth
- 28 ft
- Area
- 68 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- No
Next lake in Hennepin County
Sweeney Lake is a 68-acre mesotrophic lake in Hennepin County, Minnesota with a maximum depth of 28 feet. Water quality is graded A based on 2 sampling years through 2023. Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 80 other monitored lakes in Hennepin County, Sweeney Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 6.9 ft. Phosphorus level: 23 µg/L. Chlorophyll-a: 5.6 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.9 ft | Not graded |
| Phosphorus | 23 µg/L | Good |
| Chlorophyll-a (Algae) | 5.6 µg/L | Good |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Sweeney Lake
Compare lakeside cabins, hotels, and vacation rentals near Sweeney Lake in Hennepin 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
Sweeney 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 Jan (about 36°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 196 field readings (2011–2024) via the EPA Water Quality Portal. See the full Sweeney Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28 ft |
| Surface Area | 68 acres |
| Shoreline Length | 2.1 mi |
| Littoral Zone | 50% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Sweeney Lake
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 1991-07-01 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 60.35 | 0.11 lb |
| Black Crappie | 10.71 | 0.2 lb |
| Black Bullhead | 8.71 | 0.33 lb |
| GIS | 4.00 | 0.34 lb |
| Northern Pike | 3.28 | 3.17 lb |
| Common Carp | 2.48 | 5.07 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 1991-07-01 survey
THE PRESENT FISH POPULATION IS DOMINATED BY BLHS, SMALL CEN, CATOSTOMIDS AND CYPRINIDS. BLGS AND BLBS WERE SAMPLED WELL ABOVE MEDIAN LEVELS; BLG AVERAGED 12.06 FISH PER POUND AND HAVE A PSD=10.1. BLBS AVERAGED 8.5-8.9 INCHES TOTAL LENGTH AND 2.88 FISH PER POUND. CARP WERE SAMPLED SLIGHTLY ABOVE MEDIAN LEVELS FOR…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Sweeney Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — SweeneyFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.251 m/yr | 6 |
| Phosphorus | → Stable | -0.17 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.1 µg/L/yr | 6 |
EPA Impairment Status
Sweeney 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 MN27-0035-01 · Official waterbody report
County Ranking
Ranked #3 of 81 lakes in Hennepin County
Nearby Lakes in Hennepin County
Frequently asked questions about Sweeney Lake
What is the water quality grade for Sweeney Lake?
- Sweeney Lake in Hennepin County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.9 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 28 ft. Surface area: 67.64 acres.
Is Sweeney Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Sweeney Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Sweeney Lake?
- Sweeney Lake typically sits around 71°F at the surface in August, from 196 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Sweeney Lake?
- Sweeney Lake has a maximum depth of 28 feet. The lake covers 67.64 acres.
What fish are in Sweeney Lake?
- Fish species found in Sweeney Lake include black bullhead, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, white sucker, yellow bullhead, yellow perch. Sweeney Lake is located in Hennepin County, Minnesota.
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Where this data comes from
126 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA126 samples · 2020–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric 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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder