Seymour Lake
Orleans County, Vermont1,777 acresView mapDirections
Vermont DEC publishes the water-quality measurements for Seymour Lake. Here is what has been measured.
- Oligotrophic
- 76 ft max depth
- Public access
Seymour Lake in Orleans County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 24.6 ft visibility. Phosphorus: 7.8 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Surface area: 1777 acres.
Seymour Lake is a 1,777-acre cold, clear oligotrophic lake in Orleans County, Vermont with an estimated average depth of about 76 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 16 other monitored lakes in Orleans County, Seymour Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2025-08-15. Methodology: how these readings are compared.
Seymour Lake covers about 1,800 acres in Orleans County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Seymour Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Seymour Lake is good for
From access and monitoring records, not editorial picks.
- Clear water24.6 ft of visibility
- Boat launch1 documented ramp
- Big water1,777 acres
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 Seymour Lake is safe to swim in today is a call for the Vermont Department of Environmental Conservation and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Seymour Lake
These are the measurements Vermont DEC publishes for Seymour 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 24.6 ft down. Phosphorus 7.8 µg/L. Chlorophyll-a 1.3 µg/L. TSI 33.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 24.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 7.8µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.3µg/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 Seymour Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~76 ft est.
Surface area
1,777 acres
Public access
Yes
Listed by Vermont DEC
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Vermont has not published bathymetry for Seymour Lake.
Lake Size & Watershed
Watershed (drainage) area
21 sq mi
HydroLAKES / HydroSHEDS
Shoreline
9.9 mi
HydroLAKES / HydroSHEDS
Elevation
1,280 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Seymour LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Seymour Lake
Compare lakeside cabins, hotels, and vacation rentals near Seymour Lake in Orleans County, Vermont — 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 Seymour Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
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Fishing Seymour Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-0.49 µg/L/yr6 years
Chlorophyll-a
Improving-0.24 µg/L/yr6 years
Reservoir Info (USACE NID)
Seymour Lake is a man-made reservoir impounded by the Seymour Lake (completed 1928), built primarily for hydroelectric on the Clyde River-Tr, 12 ft tall and 75 ft long.
- Surface area
- 1,777 ac
- Normal storage
- 0 ac-ft
- Max storage
- 5,200 ac-ft
- Drainage area
- 20.19 sq mi
- Hazard class
- Low
- Owner
- GREAT BAY HYDRO CORP.
Source: USACE National Inventory of Dams, NID ID VT00023 · Operator website
Nearby Lakes in Orleans County
Frequently asked questions about Seymour Lake
Where is Seymour Lake?
- Seymour Lake is a lake in Orleans County, Vermont. Its water-quality measurements are published by Vermont DEC and shown on this page as reported.
What is the water quality of Seymour Lake?
- Seymour Lake in Orleans County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 24.6 ft visibility. Phosphorus: 7.8 µg/L. Chlorophyll-a (algae): 1.3 µg/L. Surface area: 1777 acres.
Is Seymour Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Seymour Lake?
- No published bathymetric survey covers Seymour Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 76 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 1777 acres.
Are there boat ramps on Seymour Lake?
- Seymour Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Seymour Lake. Public access is listed as yes.
Can I fish at Seymour Lake?
- Seymour Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Vermont's fish and wildlife agency, so check its current regulations before you go.
Explore Seymour Lake across LakeQuality
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Where this data comes from
171 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Vermont Dept of Environmental Conservation
1VTDECWQ171 samples · 2020–2025
Analytical methods
- EPA approved Alternate Test Procedure for 4500 P H. Has a 28 day hold without acid preservation.
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory