Ely Lake
Ely Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 17.1 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 70 ft. Surface area: 723.09 acres.
- Clarity
- 17.1 ft
- Typical in August
- 75°F
- Max depth
- 70 ft
- Area
- 723 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 24
- Open water
- 214 days
Next lake in St. Louis County
Ely Lake is a 723-acre cold, clear oligotrophic lake in St. Louis County, Minnesota with a maximum depth of 70 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 14 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available. Compared to the 67 other monitored lakes in St. Louis County, Ely Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-10. 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)
Crystal clear, you can see 17.1 ft down. Phosphorus level: 7 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.1 ft | Not graded |
| Phosphorus | 7 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Ely Lake
Compare lakeside cabins, hotels, and vacation rentals near Ely 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
Ely Lake typically sits around 75°F at the surface in August. Summer average is about 71°F. Usually warmest in Aug (about 75°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 47 field readings (2022–2025) via the EPA Water Quality Portal. See the full Ely Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 70 ft |
| Surface Area | 723 acres |
| Shoreline Length | 9.6 mi |
| Littoral Zone | 31% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Ely Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2025-08-25 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 21.38 | 0.14 lb |
| Bluntnose Minnow | 14.57 | — |
| Hybrid Sunfish | 9.28 | 0.31 lb |
| Largemouth Bass | 8.32 | 0.58 lb |
| CNM | 6.43 | — |
| JND | 6.02 | — |
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
Hybrid Sunfish
Largemouth Bass
From the 2025-08-25 survey
A targeted survey of nearshore fish species in Ely Lake was conducted on August 25th-August 28th, 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 Ely Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ElyFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ely (1771)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — ElyFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — ElyPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.14 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (74 observations).
Estimated open water season: 214 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2000-04-05 (2000) | 1996-05-09 (1996) |
| Ice-In | 1991-11-05 (1991) | 2018-12-20 (2018) |
Most recent ice-out: 2022-05-06
Reservoir Info (USACE NID)
Ely Lake is a man-made reservoir impounded by the Ely Lake (completed 1939), built primarily for recreation on the Ely Creek; gravity-type dam, 8 ft tall and 34 ft long.
- Surface area
- 780 ac
- Normal storage
- 55,620 ac-ft
- Max storage
- 61,182 ac-ft
- Drainage area
- 10 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00005 · Operator website
EPA Impairment Status
Ely Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN69-0660-00 · Official waterbody report
County Ranking
Ranked #20 of 68 lakes in St. Louis County
Nearby Lakes in St. Louis County
Frequently asked questions about Ely Lake
What is the water quality grade for Ely Lake?
- Ely Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 17.1 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Maximum depth: 70 ft. Surface area: 723.09 acres.
Is Ely Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Ely Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Ely Lake?
- Ely Lake typically sits around 75°F at the surface in August, from 47 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Ely Lake?
- Ely Lake has a maximum depth of 70 feet. The lake covers 723.09 acres.
What fish are in Ely Lake?
- Fish species found in Ely Lake include black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Ely Lake is located in St. Louis County, Minnesota.
When does Ely Lake thaw?
- Ely Lake typically has ice-out around Apr 24. Ice typically forms around Nov 24. The open water season is approximately 214 days.
Explore Ely Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
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Species activity outlook by water temperature and season
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Where this data comes from
78 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA78 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (3)
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
Ice data from Minnesota DNR Climate