Penn Lake
Hennepin County, Minnesota44 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Penn Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 7 ft max depth
- Public access
- Limited data
Penn Lake in Hennepin County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 55 µg/L. Chlorophyll-a (algae): 14.5 µg/L. Maximum depth: 7 ft. Surface area: 43.7 acres.
Penn Lake is a 44-acre productive, nutrient-rich eutrophic lake in Hennepin County, Minnesota with a maximum depth of 7 feet. The lake supports 8 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing. Compared to the 80 other monitored lakes in Hennepin County, Penn Lake ranks #53 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-14. Methodology: how these readings are compared.
What Penn Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing8 species recorded
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Penn Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Penn Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Penn Lake
These are the measurements Minnesota PCA publishes for Penn Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. Phosphorus 55 µg/L. Chlorophyll-a 14.5 µg/L. TSI 62.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 55µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 14.5µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 62 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Penn Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Penn Lake typically sits around 51°F at the surface in October. Summer average is about 80°F. Usually warmest in Jul (about 83°F) and coldest in Oct (about 51°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (51°F) to its warmest (83°F).
Typical surface water temperature by month, from 42 field readings (2010–2024) via the EPA Water Quality Portal. See the full Penn Lake water temperature breakdown →
Lake Details
Max depth
7 ft
Surface area
44 acres
Shoreline
2.3 mi
Littoral zone
98%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Elevation
801 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Penn LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Penn Lake
Compare lakeside cabins, hotels, and vacation rentals near Penn 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Penn Lake are listed below.
Top-rated places to stay near Penn Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Penn Lake
EPA Impairment Status
Penn Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN27-0004-00 · Official waterbody report
Nearby Lakes in Hennepin County
Frequently asked questions about Penn Lake
Where is Penn Lake?
- Penn Lake is a lake in Hennepin County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Penn Lake?
- Penn Lake in Hennepin County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 55 µg/L. Chlorophyll-a (algae): 14.5 µg/L. Maximum depth: 7 ft. Surface area: 43.7 acres.
Is Penn Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Penn Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Penn Lake?
- Penn Lake typically sits around 51°F at the surface in October, from 42 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Penn Lake?
- Penn Lake has a maximum depth of 7 feet. The lake covers 43.7 acres.
What fish are in Penn Lake?
- Fish species found in Penn Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, yellow perch. Penn Lake is located in Hennepin County, Minnesota.
Are there boat ramps on Penn Lake?
- Penn Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Penn Lake. Public access is listed as yes.
Can I fish at Penn Lake?
- Penn Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Penn Lake across LakeQuality
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Where this data comes from
52 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA52 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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