Nichols Lake
Nichols Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 5.1 ft visibility. Phosphorus: 20.5 µg/L. Chlorophyll-a (algae): 6.4 µg/L. Maximum depth: 31 ft. Surface area: 418.67 acres.
- Clarity
- 5.1 ft
- Typical in August
- 65°F
- Max depth
- 31 ft
- Area
- 419 acres
- Type
- Eutrophic
- Public access
- Yes
- Ice-out
- Apr 15
Next lake in St. Louis County
Nichols Lake is a 419-acre productive, nutrient-rich eutrophic lake in St. Louis County, Minnesota with a maximum depth of 31 feet (8-foot average). Water quality is graded A based on 2 sampling years through 2020. The lake supports 12 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 67 other monitored lakes in St. Louis County, Nichols Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-09-15. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Murky, only visible to about 5.1 ft. Phosphorus level: 20.5 µg/L. Chlorophyll-a: 6.4 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.1 ft | Not graded |
| Phosphorus | 20.5 µg/L | Good |
| Chlorophyll-a (Algae) | 6.4 µg/L | Good |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Nichols Lake
Compare lakeside cabins, hotels, and vacation rentals near Nichols 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.
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Water Temperature
Nichols Lake typically sits around 65°F at the surface in August. Summer average is about 68°F. Usually warmest in Jul (about 70°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 35 field readings (2019–2019) via the EPA Water Quality Portal. See the full Nichols Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 31 ft |
| Average Depth | 7.9 ft |
| Surface Area | 419 acres |
| Shoreline Length | 4.9 mi |
| Littoral Zone | 86% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Nichols LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Nichols Lake
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2025-08-11 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 9.76 | 0.18 lb |
| Largemouth Bass | 8.81 | 1.29 lb |
| CNM | 3.19 | — |
| Northern Pike | 2.55 | 1.7 lb |
| Black Crappie | 2.54 | 0.21 lb |
| Yellow Bass | 2.48 | 0.85 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
Largemouth Bass
Northern Pike
Black Crappie
From the 2025-08-11 survey
A targeted survey of nearshore fish species in Nichols Lake was conducted on August 11th-13th, 2025, by Lake Biological Monitoring and Assessment (LBMA) program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing, mini-fyke nets, and seining with a 50-foot or…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Nichols Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — NicholsFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Nichols (1819)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — NicholsFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — NicholsPublic Water Access Sites · MN DNR LakeFinder
Ice Season
Historical ice data from Minnesota DNR (7 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2010-03-29 (2010) | 2008-05-01 (2008) |
| Ice-In | 2024-11-25 (2024) | 2024-11-25 (2024) |
Most recent ice-out: 2021-04-12
EPA Impairment Status
Nichols Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN69-0627-00 · Official waterbody report
County Ranking
Ranked #19 of 68 lakes in St. Louis County
Nearby Lakes in St. Louis County
Frequently asked questions about Nichols Lake
What is the water quality grade for Nichols Lake?
- Nichols Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 5.1 ft visibility. Phosphorus: 20.5 µg/L. Chlorophyll-a (algae): 6.4 µg/L. Maximum depth: 31 ft. Surface area: 418.67 acres.
Is Nichols Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Nichols Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 6.4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Nichols Lake?
- Nichols Lake typically sits around 65°F at the surface in August, from 35 EPA Water Quality Portal field readings (2019–2019). That is a typical value for the month, not a live reading.
How deep is Nichols Lake?
- Nichols Lake has a maximum depth of 31 feet and an average depth of 7.9 feet. The lake covers 418.67 acres.
What fish are in Nichols Lake?
- Fish species found in Nichols Lake include black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Nichols Lake is located in St. Louis County, Minnesota.
When does Nichols Lake thaw?
- Nichols Lake typically has ice-out around Apr 15.
Are there boat ramps on Nichols Lake?
- Nichols Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Nichols Lake. Public access is listed as yes.
Explore Nichols Lake across LakeGrade
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Where this data comes from
15 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
MNPCA15 samples · 2020
Analytical methods
- Field measurement/observation, generic method
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
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