Long Lake
Pine County, MinnesotaLimited DataEutrophic
Long Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer.
Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake bottoms out at 24 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Long Lake is small — 77 acres alongside 2.5 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Long Lake sits at rank 13 of 19 in Pine County, in the lower half of the local distribution.
Long Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery is bass-led, with 13 documented species across the lake's records. A documented public access point at Long Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-26. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 5.7 ft. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.7 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 77.17 acres |
| Shoreline Length | 2.5 mi |
| Littoral Zone | 61% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Long Lake (14-day solunar calendar)
→ Is it safe to eat fish from Long Lake? (mercury & PFAS guide)
→ Long Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.389 m/yr | 5 |
Location
County Ranking
Ranked #13 of 19 lakes in Pine County
Cleaner Lakes Within 30 Miles
Long Lake holds Grade D. One nearby lake has a higher grade.
Nearby Lakes in Pine County
More Minnesota Lake Rankings
State Parks Near Long Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
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.
- —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
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
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2024-09-26
Monitoring stations: 1