Highland Lake
Litchfield County, Connecticut444 acresView mapDirections
CT DEEP publishes the water-quality measurements for Highland Lake. Here is what has been measured.
- Mesotrophic
- Public access
- Limited data
Highland Lake in Litchfield County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 2.3 µg/L. Surface area: 444 acres.
Highland Lake is a 444-acre mesotrophic lake in Litchfield County, Connecticut. Limited fish-species data available. Public access is available. Compared to the 11 other monitored lakes in Litchfield County, Highland Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-08-10. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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 Highland Lake is safe to swim in today is a call for the Connecticut Department of Energy and Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Highland Lake
These are the measurements CT DEEP publishes for Highland Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 17 µg/L. Chlorophyll-a 2.3 µg/L. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 17µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 2.3µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 42 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Highland Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
444 acres
Public access
Yes
Listed by CT DEEP
No bathymetric survey has been published for Highland Lake, so its depth is not documented here.
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Fishing Highland Lake
Reservoir Info (USACE NID)
Highland Lake is a man-made reservoir impounded by the Highland Lake Dam (completed 1860), built primarily for recreation on the Mad River Trib; concrete-type dam, 27 ft tall and 450 ft long.
- Surface area
- 444 ac
- Normal storage
- 8,700 ac-ft
- Max storage
- 11,800 ac-ft
- Drainage area
- 7 sq mi
- Hazard class
- High
- Owner
- Jones;Town of Winchester
Source: USACE National Inventory of Dams, NID ID CT00106 · Operator website
Nearby Lakes in Litchfield County
Frequently asked questions about Highland Lake
Where is Highland Lake?
- Highland Lake is a lake in Litchfield County, Connecticut. Its water-quality measurements are published by CT DEEP and shown on this page as reported.
What is the water quality of Highland Lake?
- Highland Lake in Litchfield County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 2.3 µg/L. Surface area: 444 acres.
Is Highland Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Highland Lake?
- Public access to Highland Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Connecticut's fish and wildlife agency, so check its current regulations before you go.
Explore Highland Lake across LakeQuality
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Where this data comes from
10 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Connecticut Department Of Energy And Environmental Protection
CT_DEP01_WQX10 samples · 2023
Analytical methods
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- Nitrate-Nitrite Nitrogen by Colorimetry
- Turbidity by Nephelometry
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.