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LakeQuality

Trident Lake

NR
Not yet rated
6.5 ft clear · Eutrophic · 93 acres
Limited DataEutrophic

Trident Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Maximum depth: 14 ft. Surface area: 93.35 acres.

Clarity
6.5 ft
Max depth
14 ft
Area
93 acres
Trend
Improving
Public access
No

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Why Trident Lake has no grade

We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Trident Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Trident Lake is a 93-acre lake in Lake County, Minnesota with a maximum depth of 14 feet. Overall water quality is improving over recent sampling years. The lake supports 9 documented fish species including bluegill, hybrid sunfish, and northern pike. No public access — the lake is private or restricted.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-06-14. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Ely

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Water quality measurements for Trident Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Murky, only visible to about 6.5 ft. Trophic State Index: 50.

MetricValueGrade
Water Clarity (Secchi Depth)6.5 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)50Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Trident Lake

Compare lakeside cabins, hotels, and vacation rentals near Trident Lake in Lake 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 Trident Lake

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Planning a whole trip? See where to stay at Minnesota’s top lakes →

Lake Details

CharacteristicValue
Maximum Depth14 ft
Surface Area93 acres
Shoreline Length2.6 mi
Littoral Zone100%
Public AccessNo

Lake Size & Watershed

Watershed (drainage) area
0 sq mi
Elevation
1,358 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Fish Species

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

Fishing Trident Lake

DNR Fisheries Survey Summary

1 survey on file from MN DNR Fisheries. Most recent: 2000-06-26 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluegill14.000.28 lb
Northern Pike8.673.15 lb
Yellow Perch6.330.09 lb
White Sucker5.331.41 lb
Walleye3.001.29 lb
Hybrid Sunfish1.000.38 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

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.

Bluegill

42 fish · 49 in · 2000-06-26
1260trophy 10456789

Northern Pike

26 fish · 1036 in · 2000-06-26
320trophy 361012141618202224262830323436

Yellow Perch

19 fish · 56 in · 2000-06-26
137056

White Sucker

16 fish · 921 in · 2000-06-26
4209101112131415161718192021

From the 2000-06-26 survey

Trident Lake is in Ecological Lake Class 12, which consists of 90 lakes in northeast Minnesota that are small, shallow, and have soft (unmineralized) water. Trident Lake is ranked as mesotrophic, according to Carlson's Trophic State Index.Trident Lake is entirely within a non-motorized portion of the Boundary Water…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Trident Lake. 1 report on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.076 m/yr5
See year-by-year chart →

EPA Impairment Status

Trident 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

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN38-0498-00 · Official waterbody report · Matched by proximity (1.44 km)

Nearby Lakes in Lake County

Frequently asked questions about Trident Lake

What is the water quality grade for Trident Lake?

Trident Lake in Lake County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Maximum depth: 14 ft. Surface area: 93.35 acres.

Is Trident Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Trident Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

How deep is Trident Lake?

Trident Lake has a maximum depth of 14 feet. The lake covers 93.35 acres.

What fish are in Trident Lake?

Fish species found in Trident Lake include bluegill, hybrid sunfish, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow perch. Trident Lake is located in Lake County, Minnesota.

Eutrophic Lakes in Minnesota

Where this data comes from

5 measurements from 2 monitoring stations, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA5 samples · 2023–2025

Analytical methods

  • Field measurement/observation, generic method
Monitoring station identifiers (2)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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