Northwood Lake-Lynn Grove Beach
Northwood Lake-Lynn Grove Beach in Rockingham County, New Hampshire has a water quality grade of B (Good). Phosphorus: 11.1 µg/L. Surface area: 11 acres.
- Area
- 11 acres
- Type
- Oligotrophic
Northwood Lake-Lynn Grove Beach is a 11-acre cold, clear oligotrophic lake in Rockingham County, New Hampshire. Water quality is graded B based on 1 sampling years through 2023. Compared to the 50 other monitored lakes in Rockingham County, Northwood Lake-Lynn Grove Beach ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-08-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyBacteria advisory
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
No clarity data. Phosphorus level: 11.1 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 11.1 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Northwood Lake-Lynn Grove Beach
Compare lakeside cabins, hotels, and vacation rentals near Northwood Lake-Lynn Grove Beach in Rockingham County, New Hampshire — 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.
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 11 acres |
No bathymetric survey has been published for Northwood Lake-Lynn Grove Beach, so its depth is not documented here.
Fishing Northwood Lake-Lynn Grove Beach
Reservoir Info (USACE NID)
Northwood Lake-Lynn Grove Beach is a man-made reservoir impounded by the Gulch Mountain Pond Dam (completed 1965), built primarily for recreation on the Tr Northwood Lake; earth-type dam, 15 ft tall and 600 ft long.
- Surface area
- 11 ac
- Normal storage
- 25 ac-ft
- Max storage
- 103 ac-ft
- Drainage area
- 0.21 sq mi
- Hazard class
- Significant
- Owner
- TOWN OF NORTHWOOD
Source: USACE National Inventory of Dams, NID ID NH00371 · Operator website · Matched by proximity (0.5 km)
EPA Impairment Status
Northwood Lake-Lynn Grove Beach is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060502-08-04 · Official waterbody report · Matched by proximity (0.27 km)
County Ranking
Ranked #13 of 51 lakes in Rockingham County
Nearby Lakes in Rockingham County
Frequently asked questions about Northwood Lake-Lynn Grove Beach
Where is Northwood Lake-Lynn Grove Beach?
- Northwood Lake-Lynn Grove Beach is a lake in Rockingham County, New Hampshire. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Northwood Lake-Lynn Grove Beach?
- Northwood Lake-Lynn Grove Beach in Rockingham County, New Hampshire has a water quality grade of B (Good). Phosphorus: 11.1 µg/L. Surface area: 11 acres.
Is Northwood Lake-Lynn Grove Beach safe to swim in?
- Good for swimming, clear water with low algae levels. Northwood Lake-Lynn Grove Beach has a water quality grade of B (Good). Always check local health department advisories before swimming.
Explore Northwood Lake-Lynn Grove Beach across LakeGrade
More New Hampshire Lake Rankings
Top 25 by overall water quality score
Top 25 by Secchi water clarity
Grade A/B + low algae filter
Panfish-rich, public access
Full state directory
Other Grade B Lakes in New Hampshire
Oligotrophic Lakes in New Hampshire
Where this data comes from
6 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
111133006 samples · 2022–2023
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database