Long Lake
Long Lake in Itasca County, Minnesota has a water quality grade of A (Excellent). Water clarity: 16.9 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 85 ft. Surface area: 134.49 acres.
- Clarity
- 16.9 ft
- Typical in August
- 58°F
- Max depth
- 85 ft
- Area
- 134 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Itasca County
Long Lake is a 134-acre cold, clear oligotrophic lake in Itasca County, Minnesota with a maximum depth of 85 feet. Water quality is graded A based on 2 sampling years through 2024. The lake supports 12 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available. Compared to the 71 other monitored lakes in Itasca County, Long Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-11. Grade methodology: LakeGrade methodology.
Watch Long Lake water quality
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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 16.9 ft down. Phosphorus level: 9.5 µg/L. Chlorophyll-a: 2.4 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.9 ft | Not graded |
| Phosphorus | 9.5 µg/L | Good |
| Chlorophyll-a (Algae) | 2.4 µg/L | Good |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long 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.
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Water Temperature
Long Lake typically sits around 58°F at the surface in August. Summer average is about 56°F. Usually warmest in Aug (about 58°F) and coldest in May (about 51°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 105 field readings (2024–2024) via the EPA Water Quality Portal. See the full Long Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 85 ft |
| Surface Area | 134 acres |
| Shoreline Length | 3.6 mi |
| Littoral Zone | 54% |
| 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 Long Lake
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 2019-06-17 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 12.14 | 0.18 lb |
| Northern Pike | 6.41 | 1.32 lb |
| Pumpkinseed | 5.39 | 0.19 lb |
| Yellow Bass | 2.67 | 0.44 lb |
| Bowfin | 1.92 | 4.48 lb |
| Brown Bullhead | 1.19 | 1 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
Northern Pike
Pumpkinseed
Yellow Bass
From the 2019-06-17 survey
Long Lake is unique, having a distinctly large shallow basin as well as another deep, steep sided basin, creating a diversity of habitat. The shoreline has moderately low development. Northern Pike and Bluegill were listed as primary management species in the 2009 lake management plan with goals of maintaining catches…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LongFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Long (0598)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.075 m/yr | 3 |
EPA Impairment Status
Long 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 MN31-0570-00 · Official waterbody report
County Ranking
Ranked #2 of 72 lakes in Itasca County
Nearby Lakes in Itasca County
Frequently asked questions about Long Lake
What is the water quality grade for Long Lake?
- Long Lake in Itasca County, Minnesota has a water quality grade of A (Excellent). Water clarity: 16.9 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 85 ft. Surface area: 134.49 acres.
Is Long Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Long Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Long Lake?
- Long Lake typically sits around 58°F at the surface in August, from 105 EPA Water Quality Portal field readings (2024–2024). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 85 feet. The lake covers 134.49 acres.
What fish are in Long Lake?
- Fish species found in Long Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, yellow bullhead, yellow perch. Long Lake is located in Itasca County, Minnesota.
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Where this data comes from
15 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA15 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 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