Cobblestone Lake
Dakota County, Minnesota35 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Cobblestone Lake. Here is what has been measured.
- Eutrophic
- Eurasian watermilfoil
- 18 ft max depth
- Limited data
Cobblestone Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 93 µg/L. Chlorophyll-a (algae): 17.5 µg/L. Maximum depth: 18 ft. Surface area: 34.73 acres.
Cobblestone Lake is a 35-acre productive, nutrient-rich eutrophic lake in Dakota County, Minnesota with a maximum depth of 18 feet. The lake supports 10 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 44 other monitored lakes in Dakota County, Cobblestone Lake ranks #22 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-06. Methodology: how these readings are compared.
Cobblestone Lake covers about 35 acres in Dakota County. Vrbo is where to look for cabins and lake homes around Cobblestone Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Cobblestone Lake is good for
From access and monitoring records, not editorial picks.
- Fishing10 species recorded
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether Cobblestone 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 Cobblestone Lake
These are the measurements Minnesota PCA publishes for Cobblestone Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.9 ft. Phosphorus 93 µg/L. Chlorophyll-a 17.5 µg/L. TSI 62.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 93µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 17.5µg/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 Cobblestone Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Cobblestone Lake typically sits around 55°F at the surface in October. Summer average is about 72°F. Usually warmest in Jul (about 77°F) and coldest in Oct (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (77°F).
Typical surface water temperature by month, from 27 field readings (2010–2024) via the EPA Water Quality Portal. See the full Cobblestone Lake water temperature breakdown →
Lake Details
Max depth
18 ft
Surface area
35 acres
Shoreline
1.3 mi
Public access
No
Listed by Minnesota PCA
Stays via Stay22
Stays near Cobblestone Lake
Compare lakeside cabins, hotels, and vacation rentals near Cobblestone Lake in Dakota 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 Cobblestone Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Cobblestone Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Cobblestone Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger.
- Met Council - Empire WrrfFarmington · 4.7 mi away · NPDES MN0045845Major
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.
Nearby Lakes in Dakota County
Frequently asked questions about Cobblestone Lake
Where is Cobblestone Lake?
- Cobblestone Lake is a lake in Dakota County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Cobblestone Lake?
- Cobblestone Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 93 µg/L. Chlorophyll-a (algae): 17.5 µg/L. Maximum depth: 18 ft. Surface area: 34.73 acres.
Is Cobblestone Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Cobblestone Lake?
- Cobblestone Lake typically sits around 55°F at the surface in October, from 27 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Cobblestone Lake?
- Cobblestone Lake has a maximum depth of 18 feet. The lake covers 34.73 acres.
What fish are in Cobblestone Lake?
- Fish species found in Cobblestone Lake include black bullhead, black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, pumpkinseed, walleye, white sucker, yellow perch. Cobblestone Lake is located in Dakota County, Minnesota.
Can I fish at Cobblestone Lake?
- Public access to Cobblestone Lake is listed as no on the lake record, so confirm before you make the trip. 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 Cobblestone Lake across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
12 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
MNPCA12 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake details from Minnesota DNR LakeFinder