Long Lake
Long Lake in Clearwater County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20.5 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 1.4 µg/L. Maximum depth: 80 ft. Surface area: 158.86 acres.
- Clarity
- 20.5 ft
- Typical in August
- 64°F
- Max depth
- 80 ft
- Area
- 159 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- May 4
- Open water
- 218 days
Next lake in Clearwater County
Long Lake is a 159-acre cold, clear oligotrophic lake in Clearwater County, Minnesota with a maximum depth of 80 feet. Water quality is graded A based on 2 sampling years through 2025. Phosphorus level is declining over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Long Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-12. Grade methodology: LakeGrade methodology.
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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)
Crystal clear, you can see 20.5 ft down. Phosphorus level: 7 µg/L. Chlorophyll-a: 1.4 µg/L. Trophic State Index: 33.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 20.5 ft | Not graded |
| Phosphorus | 7 µg/L | Good |
| Chlorophyll-a (Algae) | 1.4 µg/L | Good |
| Trophic State Index (TSI) | 33 | 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 Clearwater 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 64°F at the surface in August. Summer average is about 62°F. Usually warmest in Jul (about 66°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 164 field readings (2018–2025) via the EPA Water Quality Portal. See the full Long Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 80 ft |
| Surface Area | 159 acres |
| Shoreline Length | 3.2 mi |
| Littoral Zone | 15% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Long LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Long Lake
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2022-06-13 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 28.54 | 0.15 lb |
| Yellow Perch | 13.22 | 0.21 lb |
| Pumpkinseed | 8.14 | 0.29 lb |
| Hybrid Sunfish | 7.53 | 0.23 lb |
| Rock Bass | 7.03 | 0.24 lb |
| Yellow Bass | 3.18 | 0.53 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
Yellow Perch
Pumpkinseed
Hybrid Sunfish
From the 2022-06-13 survey
Long Lake is a 159-acre lake located in southern Clearwater County just west of Itasca State Park off of MN State Hwy 200. The lake is located adjacent to a county park with camping facilities. There is a public water access located in the park on the northwest end of the lake. The lake is a popular destination for…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lake. 4 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 (1690)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.051 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.43 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.12 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (10 observations).
Estimated open water season: 218 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-04-09 (2024) | 2022-05-09 (2022) |
| Ice-In | 2018-11-24 (2018) | 2017-12-12 (2017) |
Most recent ice-out: 2024-04-09
County Ranking
Ranked #2 of 37 lakes in Clearwater County
Nearby Lakes in Clearwater County
Frequently asked questions about Long Lake
What is the water quality grade for Long Lake?
- Long Lake in Clearwater County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20.5 ft visibility. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 1.4 µg/L. Maximum depth: 80 ft. Surface area: 158.86 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 1.4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Long Lake?
- Long Lake typically sits around 64°F at the surface in August, from 164 EPA Water Quality Portal field readings (2018–2025). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 80 feet. The lake covers 158.86 acres.
What fish are in Long Lake?
- Fish species found in Long Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rainbow trout, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Long Lake is located in Clearwater County, Minnesota.
When does Long Lake thaw?
- Long Lake typically has ice-out around May 4. Ice typically forms around Dec 8. The open water season is approximately 218 days.
Are there boat ramps on Long Lake?
- Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Long Lake. Public access is listed as yes.
Explore Long Lake across LakeGrade
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Where this data comes from
153 measurements from 2 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
MNPCA153 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
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
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