Northwood Lake-Lynn Grove Beach
Rockingham County, New Hampshire11 acresView mapDirections
NHDES publishes the water-quality measurements for Northwood Lake-Lynn Grove Beach. Here is what has been measured.
- Oligotrophic
- Limited data
Northwood Lake-Lynn Grove Beach in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 11.1 µg/L. Surface area: 11 acres.
Northwood Lake-Lynn Grove Beach is a 11-acre cold, clear oligotrophic lake in Rockingham County, New Hampshire. 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. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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 Northwood Lake-Lynn Grove Beach is safe to swim in today is a call for the New Hampshire Department of Environmental Services and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Northwood Lake-Lynn Grove Beach
These are the measurements NHDES publishes for Northwood Lake-Lynn Grove Beach, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 11.1 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 11.1µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 39 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Northwood Lake-Lynn Grove Beach
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
11 acres
No bathymetric survey has been published for Northwood Lake-Lynn Grove Beach, so its depth is not documented here.
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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)
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. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Northwood Lake-Lynn Grove Beach?
- Northwood Lake-Lynn Grove Beach in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 11.1 µg/L. Surface area: 11 acres.
Is Northwood Lake-Lynn Grove Beach safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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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)
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.