Three Island Lake
Three Island Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 29 ft visibility. Maximum depth: 66 ft. Surface area: 250.26 acres.
- Clarity
- 29 ft
- Typical in August
- 73°F
- Max depth
- 66 ft
- Area
- 250 acres
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 20
- Open water
- 222 days
Next lake in Itasca County
Why Three Island 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 Three Island 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.
Three Island Lake is a 250-acre lake in Itasca County, Minnesota with a maximum depth of 66 feet. Overall water quality is declining over recent sampling years. The lake supports 7 documented fish species including bluegill, largemouth bass, and northern pike. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-30. 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 Three Island Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Crystal clear, you can see 29 ft down. Trophic State Index: 29.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 29 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 29 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Three Island Lake
Compare lakeside cabins, hotels, and vacation rentals near Three Island Lake in Itasca 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 Three Island Lake
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Water Temperature
Three Island Lake typically sits around 73°F at the surface in August. Summer average is about 69°F. Usually warmest in Aug (about 73°F) and coldest in Sep (about 60°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 9 field readings (2022–2022) via the EPA Water Quality Portal. See the full Three Island Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 66 ft |
| Surface Area | 250 acres |
| Shoreline Length | 3.8 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crooked LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Three Island Lake
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2012-06-11 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Smallmouth Bass | 20.48 | 0.96 lb |
| Bluegill | 15.48 | 0.11 lb |
| Northern Pike | 3.08 | 2.67 lb |
| Yellow Perch | 1.55 | 0.14 lb |
| Largemouth Bass | 1.51 | 0.52 lb |
| White Sucker | 0.85 | 2.63 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.
Smallmouth Bass
Bluegill
Northern Pike
Yellow Perch
From the 2012-06-11 survey
Three Island Lake is a 235-acre lake located 5 miles east of Marcell, MN. The lake is moderately developed and has very clear water with a Secchi disk reading of 23 ft. Three Island Lake is deep with a maximum depth of 66 ft and is accessible by a portage trail from Crooked Lake. Previous water chemistry indicated low…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Three Island Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Three IslandFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.976 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (7 observations).
Estimated open water season: 222 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2017-04-09 (2017) | 2008-05-06 (2008) |
| Ice-In | 2014-11-21 (2014) | 2006-12-04 (2006) |
Most recent ice-out: 2017-04-09
EPA Impairment Status
Three Island 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 MN31-0540-00 · Official waterbody report · Matched by proximity (2.04 km)
Graded lakes near Three Island Lake
Three Island Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about Three Island Lake
What is the water quality grade for Three Island Lake?
- Three Island Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 29 ft visibility. Maximum depth: 66 ft. Surface area: 250.26 acres.
Is Three Island Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Three Island Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Three Island Lake?
- Three Island Lake typically sits around 73°F at the surface in August, from 9 EPA Water Quality Portal field readings (2022–2022). That is a typical value for the month, not a live reading.
How deep is Three Island Lake?
- Three Island Lake has a maximum depth of 66 feet. The lake covers 250.26 acres.
What fish are in Three Island Lake?
- Fish species found in Three Island Lake include bluegill, largemouth bass, northern pike, smallmouth bass, walleye, white sucker, yellow perch. Three Island Lake is located in Itasca County, Minnesota.
When does Three Island Lake thaw?
- Three Island Lake typically has ice-out around Apr 20. Ice typically forms around Nov 28. The open water season is approximately 222 days.
Are there boat ramps on Three Island Lake?
- Three Island Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Crooked Lake. Public access is listed as yes.
Explore Three Island Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
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Where this data comes from
29 measurements from 1 monitoring station, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA29 samples · 2020–2022
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