Lake Bonaparte is a 1,286-acre cold, clear oligotrophic lake in Lewis County, New York. Water quality is graded A based on 1 sampling years through 2020. The lake supports 2 documented fish species including Brown Trout and Lake Trout. Public access is available with 2 public boat landings. Compared to the 2 other monitored lakes in Lewis County, Lake Bonaparte ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2020-09-21. Grade methodology: LakeGrade methodology.
Watch Lake Bonaparte water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 15.8 ft down. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.8 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,286 acres |
| Public Access | Yes |
Where to stay near Lake Bonaparte
Compare lakeside cabins, hotels, and vacation rentals near Lake Bonaparte in Lewis County, New York — 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 Bonaparte
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Lake Bonaparte?
Get lake water-quality report cards plus the best cabin & lodging deals near Lake Bonaparte — straight to your inbox. No spam, unsubscribe anytime.
Planning a whole trip? See where to stay at New York’s top lakes →
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Lake Bonaparte
Recreation & Access
Location
County Ranking
Ranked #1 of 3 lakes in Lewis County
Nearby Lakes in Lewis County
Explore Lake Bonaparte across LakeGrade
Fish species and top-graded lakes across New York
Fish species and best lakes in Lewis County
Species activity outlook by water temperature and season
Where to stay at New York's top lakes, each with its grade
Low nutrients, clear water, excellent for swimming
New York's cleanest and most-polluted lakes, ranked
More New York Lake Rankings
Other Grade A Lakes in New York
Oligotrophic Lakes in New York
More records, surveys & data sources
Reservoir Info (USACE NID)
Lake Bonaparte is a man-made reservoir impounded by the Alpina Dam (completed 1933), built primarily for other on the BONAPARTE CREEK; concrete-type dam, 7 ft tall and 120 ft long.
- Surface area
- 1,286 ac
- Normal storage
- 39,739 ac-ft
- Max storage
- 39,739 ac-ft
- Drainage area
- 18.4 sq mi
- Hazard class
- Low
- Owner
- NIAGARA MOHAWK POWER CORPORATION
Source: USACE National Inventory of Dams, NID ID NY00778 · Operator website
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Bonaparte under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Gouverneur Minerals Div #4 MineDiana, Town Of · 2.3 mi away · NPDES NY0110779Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2020-09-21
Monitoring stations: 1