Jacobs Lake
Jacobs Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.5 ft visibility. Maximum depth: 9 ft. Surface area: 89.8 acres.
- Clarity
- 4.5 ft
- Max depth
- 9 ft
- Area
- 90 acres
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 29
- Open water
- 206 days
Next lake in St. Louis County
Why Jacobs 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 Jacobs 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.
Jacobs Lake is a 90-acre lake in St. Louis County, Minnesota with a maximum depth of 9 feet (4-foot average). Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-09-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Jacobs Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 4.5 ft. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Jacobs Lake
Compare lakeside cabins, hotels, and vacation rentals near Jacobs 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 Jacobs Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 9 ft |
| Average Depth | 4 ft |
| Surface Area | 90 acres |
| Shoreline Length | 2.6 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Island Lake (North)Public
Fishing Jacobs Lake
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 2008-06-18 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 233.11 | 0.3 lb |
| Yellow Perch | 67.08 | 0.18 lb |
| Bluegill | 38.95 | 0.27 lb |
| CSH | 22.00 | — |
| TPM | 12.00 | — |
| Black Crappie | 10.72 | 0.33 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.
Black Bullhead
Yellow Perch
Bluegill
Black Crappie
From the 2008-06-18 survey
Jacobs is an 88-acre lake with 88 acres (100%) of littoral area and a maximum depth of 9 feet. The lake is heavily vegetated and located 9 miles north of Duluth, Minnesota. There is no public access to Jacobs Lake. Jacobs was initially surveyed in 1964 and again in 1997 by DNR fisheries. A population assessment was…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Jacobs Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — JacobsFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Jacobs (0465)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.231 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (32 observations).
Estimated open water season: 206 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-14 (2024) | 2022-05-07 (2022) |
| Ice-In | 2019-11-02 (2019) | 2009-12-02 (2009) |
Most recent ice-out: 2024-03-14
EPA Impairment Status
Jacobs Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN69-0372-02 · Official waterbody report · Matched by proximity (2.64 km)
Nearby Lakes in St. Louis County
Frequently asked questions about Jacobs Lake
What is the water quality grade for Jacobs Lake?
- Jacobs Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.5 ft visibility. Maximum depth: 9 ft. Surface area: 89.8 acres.
Is Jacobs Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Jacobs 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 Jacobs Lake?
- Jacobs Lake has a maximum depth of 9 feet and an average depth of 4 feet. The lake covers 89.8 acres.
When does Jacobs Lake thaw?
- Jacobs Lake typically has ice-out around Apr 29. Ice typically forms around Nov 21. The open water season is approximately 206 days.
Are there boat ramps on Jacobs Lake?
- Jacobs Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Island Lake (North). Public access is listed as yes.
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Where this data comes from
16 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA16 samples · 2020
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (1)
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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate