Agnes Lake
St. Louis County, MinnesotaLimited DataOligotrophic
On the LakeGrade scale Agnes Lake grades a B, with clarity at 13.5 ft and phosphorus readings still being added placing it above the Minnesota median. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
A TSI value of 40 puts Agnes Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 30 ft puts Agnes Lake in the middle of Minnesota's depth distribution. Agnes Lake covers 1,045 acres alongside 13.0 miles of shoreline, large enough that conditions can vary meaningfully between bays. Among the 187 graded lakes in St. Louis County, Agnes Lake sits at rank 69, above the county median.
No invasive species are currently listed at Agnes Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Agnes Lake, one of 10 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-06-21. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 13.5 ft. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.5 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 40 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 30 ft |
| Surface Area | 1.0K acres |
| Shoreline Length | 13 mi |
| Littoral Zone | 43% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Agnes Lake (14-day solunar calendar)
→ Is it safe to eat fish from Agnes Lake? (mercury & PFAS guide)
→ Agnes Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.53 m/yr | 2 |
Location
County Ranking
Ranked #69 of 187 lakes in St. Louis County
Nearby Lakes in St. Louis County
More Minnesota Lake Rankings
Other Grade B Lakes in Minnesota
Oligotrophic Lakes in Minnesota
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 2016-06-20 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| CIS | 14.67 | 0.36 lb |
| Walleye | 7.42 | 0.96 lb |
| Yellow Perch | 6.00 | 0.15 lb |
| White Sucker | 5.05 | 1.94 lb |
| Northern Pike | 4.08 | 2.44 lb |
| SIL | 3.56 | — |
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.
CIS
Walleye
Yellow Perch
White Sucker
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…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Agnes Lake. 1 report on file.
- —Fisheries Lake Survey — AgnesFisheries Lake Survey · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2024-06-21
Monitoring stations: 4