Upper Estuary Lake
St. Louis County, Minnesota10,255 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Upper Estuary Lake. Here is what has been measured.
- Eutrophic
- 55 ft max depth
- Public access
- Limited data
Upper Estuary Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.9 ft visibility. Phosphorus: 49.5 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Maximum depth: 55 ft. Surface area: 10255.25 acres.
Upper Estuary Lake is a 10,255-acre productive, nutrient-rich eutrophic lake in St. Louis County, Minnesota with a maximum depth of 55 feet. The lake supports 33 documented fish species including American eel, black bullhead, and black crappie. Public access is available with 2 public boat landings. Compared to the 67 other monitored lakes in St. Louis County, Upper Estuary Lake ranks #62 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
What Upper Estuary Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Fishing33 species recorded
- Deep water55 ft surveyed max depth
- Big water10,255 acres
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 Upper Estuary 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 Upper Estuary Lake
These are the measurements Minnesota PCA publishes for Upper Estuary 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 1.9 ft of visibility. Phosphorus 49.5 µg/L. Chlorophyll-a 1.7 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 49.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 1.7µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Upper Estuary Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
55 ft
Surface area
10,255 acres
Shoreline
195.5 mi
Littoral zone
100%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Sajac Memorial ParkPublic
- Fond du Lac CampgroundPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fish Species
Click a species to see every lake where it is documented.
Fishing Upper Estuary Lake
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Upper Estuary Lake under Clean Water Act (NPDES) discharge permits.
- Murphy Oil Usa IncEsko · 4.1 mi away · NPDES MN0041556
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 St. Louis County
Frequently asked questions about Upper Estuary Lake
Where is Upper Estuary Lake?
- Upper Estuary Lake is a lake in St. Louis County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Upper Estuary Lake?
- Upper Estuary Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.9 ft visibility. Phosphorus: 49.5 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Maximum depth: 55 ft. Surface area: 10255.25 acres.
Is Upper Estuary Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Upper Estuary Lake?
- Upper Estuary Lake has a maximum depth of 55 feet. The lake covers 10255.25 acres.
What fish are in Upper Estuary Lake?
- Fish species found in Upper Estuary Lake include American eel, black bullhead, black crappie, bluegill, brook trout, brown bullhead, brown trout, burbot, channel catfish, common carp, freshwater drum, gizzard shad, lake sturgeon, largemouth bass, longnose sucker, muskellunge, northern pike, pumpkinseed, quillback, rainbow smelt, rainbow trout, rock bass, shorthead redhorse, silver redhorse, smallmouth bass, splake, tiger muskellunge, walleye, white bass, white perch, white sucker, yellow bullhead, yellow perch. Upper Estuary Lake is located in St. Louis County, Minnesota.
Are there boat ramps on Upper Estuary Lake?
- Upper Estuary Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Sajac Memorial Park, Fond du Lac Campground. Public access is listed as yes.
Can I fish at Upper Estuary Lake?
- Upper Estuary Lake has 2 documented boat landings 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.
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Where this data comes from
43 measurements from 2 monitoring stations, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA43 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
Named boat-access points from the USGS National Boat Ramps inventory