Junior Lake
Penobscot County, MaineView mapDirections
Maine DEP publishes the water-quality measurements for Junior Lake. Here is what has been measured.
- Oligotrophic
Junior Lake in Penobscot County, Maine has water-quality measurements published by Maine DEP, shown here as reported. Water clarity: 25.9 ft visibility. Phosphorus: 6 µg/L. Chlorophyll-a (algae): 2 µg/L.
Junior Lake is a cold, clear oligotrophic lake in Penobscot County, Maine. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-08-01. Methodology: how these readings are compared.
What Junior Lake is good for
From access and monitoring records, not editorial picks.
- Clear water25.9 ft of visibility
Swimming conditions
Readings onlyLow algae
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. Check local advisories before you swim.
Whether Junior Lake is safe to swim in today is a call for the Maine Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Junior Lake
These are the measurements Maine DEP publishes for Junior Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 25.9 ft down. Phosphorus 6 µg/L. Chlorophyll-a 2 µg/L. TSI 33.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 25.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 6µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 2µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 33 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Junior Lake
Answers come straight from the public measurements and survey records on this page.
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Fishing Junior Lake
Water quality readings over time
3 seasons of samples on record (2020–2022). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving3 years
Phosphorus
Worsening+0.5 µg/L/yr3 years
Chlorophyll-a
Improving-0.25 µg/L/yr3 years
Nearby Lakes in Penobscot County
Frequently asked questions about Junior Lake
Where is Junior Lake?
- Junior Lake is a lake in Penobscot County, Maine. Its water-quality measurements are published by Maine DEP and shown on this page as reported.
What is the water quality of Junior Lake?
- Junior Lake in Penobscot County, Maine has water-quality measurements published by Maine DEP, shown here as reported. Water clarity: 25.9 ft visibility. Phosphorus: 6 µg/L. Chlorophyll-a (algae): 2 µg/L.
Is Junior Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Junior Lake across LakeQuality
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Oligotrophic Lakes in Maine
Where this data comes from
37 measurements from 1 monitoring station, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples37 samples · 2020–2022
Monitoring station identifiers (1)
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.