North Long Lake
Ramsey County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for North Long Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- 2 aquatic invasives
- Public access
North Long Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.5 ft visibility. Phosphorus: 102 µg/L. Chlorophyll-a (algae): 30.9 µg/L.
North Long Lake is a productive, nutrient-rich eutrophic lake in Ramsey County, Minnesota. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 43 other monitored lakes in Ramsey County, North Long Lake ranks #39 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-15. Methodology: how these readings are compared.
Swimming conditions
Readings onlyAlgae risk
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. North Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether North Long Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for North Long Lake
These are the measurements Minnesota PCA publishes for North Long Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.5 ft of visibility. Phosphorus 102 µg/L. Chlorophyll-a 30.9 µg/L. TSI 66.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 102µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 30.9µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 66 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about North Long Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
North Long Lake typically sits around 67°F at the surface in September. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Mar (about 39°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (39°F) to its warmest (75°F).
Typical surface water temperature by month, from 443 field readings (2010–2025) via the EPA Water Quality Portal. See the full North Long Lake water temperature breakdown →
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for North Long Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — North LongPublic Water Access Sites · MN DNR LakeFinder
Stays via Stay22
Stays near North Long Lake
Compare lakeside cabins, hotels, and vacation rentals near North Long Lake in Ramsey 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around North Long Lake are listed below.
Top-rated places to stay near North Long Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fishing North Long Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Improving-1.7 µg/L/yr6 years
Chlorophyll-a
Improving-0.95 µg/L/yr6 years
EPA Impairment Status
North 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
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN62-0067-01 · Official waterbody report
Nearby Lakes in Ramsey County
Frequently asked questions about North Long Lake
Where is North Long Lake?
- North Long Lake is a lake in Ramsey County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of North Long Lake?
- North Long Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.5 ft visibility. Phosphorus: 102 µg/L. Chlorophyll-a (algae): 30.9 µg/L.
Is North Long Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. North Long Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of North Long Lake?
- North Long Lake typically sits around 67°F at the surface in September, from 443 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Can I fish at North Long Lake?
- Public access to North Long Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore North Long Lake across LakeQuality
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Where this data comes from
323 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
MNPCA323 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- Turbidity by Nephelometry
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database