Montgomery Lake is a cold, clear oligotrophic lake in Sullivan County, New York. Water quality is graded B based on 1 sampling years through 2020. Compared to the 3 other monitored lakes in Sullivan County, Montgomery Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2020-09-19. Grade methodology: LakeGrade methodology.
Watch Montgomery Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 13.9 ft. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.9 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Montgomery Lake
Compare lakeside cabins, hotels, and vacation rentals near Montgomery Lake in Sullivan 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 Montgomery Lake
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 Montgomery Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Montgomery Lake — straight to your inbox. No spam, unsubscribe anytime.
Planning a whole trip? See where to stay at New York’s top lakes →
Fishing Montgomery Lake
Location
County Ranking
Ranked #2 of 4 lakes in Sullivan County
Nearby Lakes in Sullivan County
Explore Montgomery Lake across LakeGrade
Fish species and top-graded lakes across New York
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 B Lakes in New York
Oligotrophic Lakes in New York
More records, surveys & data sources
EPA Impairment Status
Montgomery Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NY1401-0091 · Official waterbody report · Matched by proximity (0.42 km)
Regulated Pollution Sources Nearby
8 EPA-permitted facilities operate within about 5 miles of Montgomery Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Eldred PreserveEldred · 4 mi away · NPDES NY0281239Recent violation
- Aqua Pa Wastewater Inc Mast Hope WwtfLackawaxen · 4.7 mi away · NPDES PA0060496Recent violation
- 696 State Highway Route 580 Sftf (Fka David Holbert Sftf)Lackawaxen · 4.8 mi away · NPDES PA0065129Recent violation
- Barryville Shop - County DpwBarryville · 1.9 mi away · NPDES NY0264202
- Rudd HouseBarryville · 2.1 mi away · NPDES NY0219274
- New Hope Manor IncBarryville · 3.3 mi away · NPDES NY0207586
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2020-09-19
Monitoring stations: 1