Long Lake
Long Lake in Pine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Maximum depth: 24 ft. Surface area: 77.17 acres.
- Clarity
- 6.5 ft
- Typical in August
- 75°F
- Max depth
- 24 ft
- Area
- 77 acres
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Pine County
Why Long 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 Long 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.
Long Lake is a 77-acre lake in Pine County, Minnesota with a maximum depth of 24 feet. Overall water quality is declining over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-14. 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 Long Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 6.5 ft. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Lake in Pine 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 Long Lake
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Water Temperature
Long Lake typically sits around 75°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 76°F) and coldest in Apr (about 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 89 field readings (2016–2025) via the EPA Water Quality Portal. See the full Long Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 77 acres |
| Shoreline Length | 2.5 mi |
| Littoral Zone | 61% |
| 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
4 surveys on file from MN DNR Fisheries. Most recent: 2023-06-27 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 11.94 | 0.15 lb |
| Northern Pike | 2.77 | 1.62 lb |
| Largemouth Bass | 2.46 | 0.87 lb |
| Black Crappie | 2.40 | 0.21 lb |
| Pumpkinseed | 1.71 | 0.19 lb |
| Brown Bullhead | 1.59 | 0.57 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
Largemouth Bass
Black Crappie
From the 2023-06-27 survey
Long Lake is a 75-acre lake located in Pine County. The lake is primarily suited for Northern Pike, Black Crappie, and Bluegill. Populations of Largemouth Bass are also present. To assess fish populations, a survey was conducted using trap and gill nets in June 2023. The Northern Pike gill net catch was 20 fish,…
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 (0369)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.227 m/yr | 6 |
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 MN58-0107-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Long Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Willow River WwtpWillow River · 1.9 mi away · NPDES MN0021971Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Pine County
Frequently asked questions about Long Lake
What is the water quality grade for Long Lake?
- Long Lake in Pine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Maximum depth: 24 ft. Surface area: 77.17 acres.
Is Long Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Long 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 Long Lake?
- Long Lake typically sits around 75°F at the surface in August, from 89 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 24 feet. The lake covers 77.17 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, shorthead redhorse, white crappie, white sucker, yellow bullhead. Long Lake is located in Pine County, Minnesota.
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.
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Where this data comes from
94 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA94 samples · 2020–2025
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory