Lake St Croix
Pierce County, Minnesota8,393 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Lake St Croix. Here is what has been measured.
- Eutrophic
- Eurasian watermilfoil
- 78 ft max depth
- Public access
- Limited data
Lake St Croix in Pierce County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 32.5 µg/L. Maximum depth: 78 ft. Surface area: 8393.04 acres.
Minnesota DNR's Standard Survey on July 7, 2009 caught 1.12 walleye per gill net at Lake St Croix. DNR survey details →
Lake St Croix is a 8,393-acre productive, nutrient-rich eutrophic lake in Pierce County, Minnesota with a maximum depth of 78 feet. Water clarity is improving over recent sampling years. The lake supports 36 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-05. Methodology: how these readings are compared.
What Lake St Croix is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing36 species recorded
- Deep water78 ft surveyed max depth
- Big water8,393 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 Lake St Croix 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 Lake St Croix
These are the measurements Minnesota PCA publishes for Lake St Croix, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.2 ft. Phosphorus 32.5 µg/L. TSI 51.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 32.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 51 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake St Croix
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on July 7, 2009 caught 1.12 walleye per gill net at Lake St Croix.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake St Croix’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2024-10-21 (Standard Survey).
18 surveys on file · most recent 2024-10-21 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Smallmouth Bass | 4.97 | 5–19 in 2024-10-21 | 0.9 lb |
| Common Carp | 4.04 | 19–31 in 2024-04-15 | 4.74 lb |
| Freshwater Drum | 2.99 | 5–13 in 2024-10-21 | 0.61 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Smallmouth Bass
Common Carp
Freshwater Drum
From the 2024-10-21 survey
A gill net survey was conducted on Lake St. Croix in 2024 and sampled 970 fish represented by 28 different species and one hybrid. Over 51% of the fish sampled were considered game fish species (those species which have defined creel limits). Composition of the top five game fish species sampled were 29.8% Yellow…
Lake Details
Max depth
78 ft
Surface area
8,393 acres
Shoreline
124.5 mi
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- St. Croix Bluffs Regional ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lake St Croix
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Top-rated places to stay near Lake St Croix
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Follow Lake St Croix’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Lake St Croix
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Stable
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Worsening+7.2 µg/L/yr5 years
Nearby Lakes in Pierce County
Frequently asked questions about Lake St Croix
Where is Lake St Croix?
- Lake St Croix is a lake in Pierce County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Lake St Croix?
- Lake St Croix in Pierce County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 32.5 µg/L. Maximum depth: 78 ft. Surface area: 8393.04 acres.
Is Lake St Croix safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake St Croix?
- Lake St Croix has a maximum depth of 78 feet. The lake covers 8393.04 acres.
What fish are in Lake St Croix?
- Fish species found in Lake St Croix include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, flathead catfish, freshwater drum, gizzard shad, golden redhorse, highfin carpsucker, hybrid sunfish, lake sturgeon, largemouth bass, longnose gar, mooneye, muskellunge, northern pike, paddlefish, quillback, river carpsucker, river redhorse, rock bass, sauger, shorthead redhorse, shortnose gar, silver redhorse, smallmouth bass, smallmouth buffalo, spotted sucker, walleye, walleye/sauger, white bass, white crappie, white sucker, yellow perch. Lake St Croix is located in Pierce County, Minnesota.
What did the DNR fisheries survey find at Lake St Croix?
- Minnesota DNR's Standard Survey on July 7, 2009 caught 1.12 walleye per gill net at Lake St Croix. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake St Croix’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Lake St Croix?
- Lake St Croix has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include St. Croix Bluffs Regional Park. Public access is listed as yes.
Can I fish at Lake St Croix?
- Lake St Croix 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 Lake St Croix across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Minnesota's cleanest lakes, ranked on agency measurements
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Compare Lake St Croix With Nearby Lakes
Where this data comes from
15 measurements from 2 monitoring stations, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Minnesota Water Science Center
USGS-MN10 samples · 2020 - Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2023
Analytical methods
- Secchi disk method
- P, wu, WCA, persulfate CF color
- Field measurement/observation, generic method
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
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory