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LakeQuality

Lac la Croix Lake

St. Louis County, Minnesota1,045 acresView mapDirections

Minnesota PCA publishes the water-quality measurements for Lac la Croix Lake. Here is what has been measured.

Clarity
2.5 ft
Murkier than most
Secchi · sampled 2025
Max depth
30 ft
Bathymetric survey
Area
1,045 acres
Surface area
Shoreline
13 mi
Measured length
  • Impaired · Mercury
  • 30 ft max depth
  • Limited data

Lac la Croix Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.5 ft visibility. Maximum depth: 30 ft. Surface area: 1044.61 acres.

Minnesota DNR's Standard Survey on June 20, 2016 caught 8.00 walleye per gill net at Lac la Croix Lake. Length samples in the latest survey that recorded them ran 6–25 inches. DNR survey details →

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Lac la Croix Lake is a 1,045-acre lake in St. Louis County, Minnesota with a maximum depth of 30 feet. The lake supports 10 documented fish species including black crappie, cisco species, and northern pike. No public access — the lake is private or restricted.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-04. Methodology: how these readings are compared.

What Lac la Croix Lake is good for

From access and monitoring records, not editorial picks.

  • Fishing10 species recorded
  • Deep water30 ft surveyed max depth
  • Big water1,045 acres

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Lac la Croix Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

Whether Lac la Croix 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.

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Water quality measurements for Lac la Croix Lake

These are the measurements Minnesota PCA publishes for Lac la Croix 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 2.5 ft of visibility. TSI 64.

Water quality readings
MeasureReadingWhere it sits
Water clarity (Secchi depth)2.5ftMeasured, not scored

How deep a black-and-white disk stays visible from the surface. Higher is clearer.

Total phosphorusNo reading

The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.

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.64Eutrophic
OligotrophicMesotrophicEutrophicHypereutrophic

High nutrients, frequent algae, reduced clarity

Ask about Lac la Croix Lake

Answers come straight from the public measurements and survey records on this page.

DNR fisheries survey

Minnesota DNR's Standard Survey on June 20, 2016 caught 8.00 walleye per gill net at Lac la Croix Lake. Length samples in the latest survey that recorded them ran 6–25 inches.

A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lac la Croix Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.

DNR Fisheries Survey Summary

2 surveys on file from MN DNR Fisheries. Most recent: 2016-06-20 (Standard Survey).

2 surveys on file · most recent 2016-06-20 (Standard Survey)

SpeciesCatch rate (CPUE)SizeAvg weight
Walleye
7.42
6–25 in
2016-06-20
0.96 lb
Yellow Perch
6.00
4–9 in
2016-06-20
0.15 lb
White Sucker
5.05
0–20 in
2016-06-20
1.94 lb
Northern Pike
4.08
12–40 in
2016-06-20
2.44 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.

Walleye

72 fish · 6–25 in · 2016-06-20
1470trophy 24″681012141618202224

Yellow Perch

90 fish · 4–9 in · 2016-06-20
45230456789

White Sucker

76 fish · 0–20 in · 2016-06-20
147002468101214161820

Northern Pike

27 fish · 12–40 in · 2016-06-20
630trophy 36″121416182022242628303234363840

From the 2016-06-20 survey

Agnes Lake is located about 24 miles northwest of Ely and is within the Superior National Forest's Boundary Waters Canoe Area Wilderness (BWCAW). There are four accesses, three of which are portages and one is a water route. Accesses consist of the inlet of the Moose River, a 160 rod portage to the Oyster River, a 24…

Source: MN DNR LakeFinder Fisheries Lake Survey

Lake Details

Max depth

30 ft

Surface area

1,045 acres

Shoreline

13 mi

Littoral zone

43%

Share shallower than 15 ft

Public access

No

Listed by Minnesota PCA

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Stays near Lac la Croix Lake

Compare lakeside cabins, hotels, and vacation rentals near Lac la Croix Lake in St. Louis 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 Lac la Croix Lake

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Fish Species

Click a species to see every lake where it is documented.

Fishing Lac la Croix Lake

EPA Impairment Status

Lac la Croix Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Designated uses not supporting: Fish consumption.

Source: EPA ATTAINS assessment unit MN69-0224-00 · Official waterbody report

Nearby Lakes in St. Louis County

Frequently asked questions about Lac la Croix Lake

Where is Lac la Croix Lake?

Lac la Croix 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 Lac la Croix Lake?

Lac la Croix Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.5 ft visibility. Maximum depth: 30 ft. Surface area: 1044.61 acres.

Measurements on this page ↑

Is Lac la Croix Lake safe to swim in?

Nutrient and algae readings are not a swimming clearance. Lac la Croix Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

Swimming on this page ↑

How deep is Lac la Croix Lake?

Lac la Croix Lake has a maximum depth of 30 feet. The lake covers 1044.61 acres.

What fish are in Lac la Croix Lake?

Fish species found in Lac la Croix Lake include black crappie, cisco species, northern pike, rock bass, sauger, shorthead redhorse, smallmouth bass, walleye, white sucker, yellow perch. Lac la Croix Lake is located in St. Louis County, Minnesota.

Fish on this page ↑

What did the DNR fisheries survey find at Lac la Croix Lake?

Minnesota DNR's Standard Survey on June 20, 2016 caught 8.00 walleye per gill net at Lac la Croix Lake. Length samples in the latest survey that recorded them ran 6–25 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lac la Croix Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.

DNR on this page ↑

Can I fish at Lac la Croix Lake?

Public access to Lac la Croix 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.

Where this data comes from

1 measurement from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA1 sample · 2025

Analytical methods

  • Field measurement/observation, generic method
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 details from Minnesota DNR LakeFinder