Long Lake
Long Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 83 ft. Surface area: 201.57 acres.
- Clarity
- 10 ft
- Typical in August
- 72°F
- Max depth
- 83 ft
- Area
- 202 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Beltrami County
Long Lake is a 202-acre mesotrophic lake in Beltrami County, Minnesota with a maximum depth of 83 feet. Water quality is graded A based on 2 sampling years through 2021. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 84 other monitored lakes in Beltrami County, Long Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-27. Grade methodology: LakeGrade methodology.
Watch Long Lake water quality
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Swimming Safety
Grade onlyLow algae
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)
Good clarity, visible to about 10 ft. Phosphorus level: 17 µg/L. Chlorophyll-a: 4.9 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 17 µg/L | Good |
| Chlorophyll-a (Algae) | 4.9 µg/L | Good |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Lake in Beltrami 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 72°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 73°F) and coldest in Sep (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2019–2021) via the EPA Water Quality Portal.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 83 ft |
| Surface Area | 202 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 21% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Long Lake
DNR Fisheries Survey Summary
1 survey on file from MN DNR Fisheries. Most recent: 1986-06-25 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 57.00 | 0.16 lb |
| Hybrid Sunfish | 9.50 | 0.16 lb |
| Pumpkinseed | 8.50 | 0.2 lb |
| Northern Pike | 3.38 | 2.14 lb |
| Yellow Perch | 2.38 | 0.21 lb |
| White Sucker | 1.50 | 2 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 1986-06-25 survey
HIGH NORTHERN PIKE POPULATION. BECAUSE OF SEVERE DROPOFF AROUND LAKE, RELIABLE NETTING IS DIFFICULT LOCAL FISHING REPORTS INDICATE A BETTER FISH POPU- LATION THAN REVEALED THAN REVEALED BY TEST NETTING
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 — BuzzleFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Buzzle (1729)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — BuzzlePublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.46 m/yr | 2 |
| Phosphorus | ↓ Declining | +2 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +2.3 µg/L/yr | 2 |
EPA Impairment Status
Long 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 MN04-0295-00 · Official waterbody report
County Ranking
Ranked #6 of 85 lakes in Beltrami County
Nearby Lakes in Beltrami County
Frequently asked questions about Long Lake
What is the water quality grade for Long Lake?
- Long Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 83 ft. Surface area: 201.57 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 4.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Long Lake?
- Long Lake typically sits around 72°F at the surface in August, from 29 EPA Water Quality Portal field readings (2019–2021). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 83 feet. The lake covers 201.57 acres.
Explore Long Lake across LakeGrade
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Where this data comes from
26 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA26 samples · 2020–2021
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