Lake Iroquois
Chittenden County, Vermont229 acresView mapDirections
Vermont DEC publishes the water-quality measurements for Lake Iroquois. Here is what has been measured.
- Eutrophic
- 54 ft max depth
- Public access
Lake Iroquois in Chittenden County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 11.8 ft visibility. Phosphorus: 19.1 µg/L. Chlorophyll-a (algae): 8.4 µg/L. Surface area: 229 acres.
Lake Iroquois is a 229-acre productive, nutrient-rich eutrophic lake in Chittenden County, Vermont with an estimated average depth of about 54 feet. Phosphorus level is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 7 other monitored lakes in Chittenden County, Lake Iroquois ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2025-08-18. Methodology: how these readings are compared.
Lake Iroquois covers about 230 acres in Chittenden County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Lake Iroquois, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Iroquois is good for
From access and monitoring records, not editorial picks.
- Clear water11.8 ft of visibility
- Boat launch1 documented ramp
Swimming conditions
Readings onlyModerate 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 Lake Iroquois 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 Lake Iroquois
These are the measurements Vermont DEC publishes for Lake Iroquois, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11.8 ft. Phosphorus 19.1 µg/L. Chlorophyll-a 8.4 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 19.1µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 8.4µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 47 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Iroquois
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~54 ft est.
Surface area
229 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 Lake Iroquois.
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Shoreline
3 mi
HydroLAKES / HydroSHEDS
Elevation
682 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
- Lake IroquoisPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lake Iroquois
Compare lakeside cabins, hotels, and vacation rentals near Lake Iroquois in Chittenden 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 Lake Iroquois
Prices for Oct 30–Nov 1, 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 Lake Iroquois
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Worsening+1.36 µg/L/yr6 years
Chlorophyll-a
Improving-0.76 µg/L/yr6 years
Reservoir Info (USACE NID)
Lake Iroquois is a man-made reservoir impounded by the Lake Iroquois (completed 1870), built primarily for other on the Patrick Brook; concrete-type dam, 7 ft tall and 98 ft long.
- Surface area
- 229 ac
- Normal storage
- 0 ac-ft
- Max storage
- 1,515 ac-ft
- Drainage area
- 3.78 sq mi
- Hazard class
- Low
- Owner
- IROQUOIS MANUFACTURING CO
All listed purposes: Other;Recreation.
Source: USACE National Inventory of Dams, NID ID VT00060 · Operator website
Nearby Lakes in Chittenden County
Frequently asked questions about Lake Iroquois
Where is Lake Iroquois?
- Lake Iroquois is a lake in Chittenden County, Vermont. Its water-quality measurements are published by Vermont DEC and shown on this page as reported.
What is the water quality of Lake Iroquois?
- Lake Iroquois in Chittenden County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 11.8 ft visibility. Phosphorus: 19.1 µg/L. Chlorophyll-a (algae): 8.4 µg/L. Surface area: 229 acres.
Is Lake Iroquois safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Iroquois?
- No published bathymetric survey covers Lake Iroquois, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 54 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 229 acres.
Are there boat ramps on Lake Iroquois?
- Lake Iroquois has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Iroquois. Public access is listed as yes.
Can I fish at Lake Iroquois?
- Lake Iroquois 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.
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Where this data comes from
243 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
1VTDECWQ243 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