Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Belknap County Lake Quality

New Hampshire, 55 lakes, measured by NHDES

Belknap County in New Hampshire carries 55 monitored lakes — one of the lake-richer counties in our dataset. Coverage that dense usually reflects active lake-association sampling alongside state-agency monitoring. 24 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The county-wide picture is low-to-moderate phosphorus with clear summer transparency across most monitored lakes.

Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake Winnisquam Mohawk Isl-Deep Spot has the lowest nutrient and algae readings in the county.

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Quick Answers for Belknap County

Cleanest lakes in Belknap County →Best swimming lakes in New Hampshire →

Planning a trip? Check special fishing regulations for Lake Winnisquam Mohawk Isl-Deep Spot — or check the official New Hampshire fishing regulations.

All Lakes in Belknap County

55 lakes · 24 ranked on readings, 31 without enough sampling24 lakes ranked on readings · 31 without enough sampling, hidden

Include not-rated lakes (31)

#	Lake	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	Lake Winnisquam Mohawk Isl-Deep SpotBelknap	No recent samples	10.4 µg/L	1.2 µg/L	No recent samples	No recent samples	Not recorded
2	Lake Winnisquam Pot Island-Deep SpotBelknap	No recent samples	6.6 µg/L	0.8 µg/L	No recent samples	No recent samples	Not recorded
3	Crystal Lake-OutletBelknap	No recent samples	11.6 µg/L	No recent samples	No recent samples	No recent samples	✓ Public
4	Hermit Lake-Deep SpotBelknap	No recent samples	12.7 µg/L	12.9 µg/L	No recent samples	No recent samples	Not recorded
5	Hills Pond-Deep SpotBelknap	No recent samples	12.9 µg/L	6.1 µg/L	No recent samples	No recent samples	✓ Public
6	Lake Waukewan-Perkins CoveBelknap	No recent samples	8.1 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
7	Lake Winnisquam-OutletBelknap	No recent samples	9.8 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
8	Loon Pond-Deep SpotBelknap	No recent samples	9.8 µg/L	5.7 µg/L	No recent samples	No recent samples	✓ Public
9	Lower Suncook Pond-Deep SpotBelknap	No recent samples	10.7 µg/L	1.9 µg/L	No recent samples	No recent samples	Not recorded
10	Opechee Bay-Deep Spot LakeBelknap	No recent samples	8.4 µg/L	No recent samples	No recent samples	No recent samples	✓ Public
11	Pemigewasset Lake-OutletBelknap	No recent samples	8.1 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
12	Pemigewasset Lake-VlapBelknap	No recent samples	15.4 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
13	Sawyer Lake-Deep SpotBelknap	No recent samples	9.9 µg/L	3 µg/L	No recent samples	No recent samples	Not recorded
14	Upper Suncook Pond-Deep SpotBelknap	No recent samples	11 µg/L	3.8 µg/L	No recent samples	No recent samples	Not recorded
15	Wicwas Lake-Deep SpotBelknap	No recent samples	10.7 µg/L	4 µg/L	No recent samples	No recent samples	Not recorded
16	Wicwas Lake-East CoveBelknap	No recent samples	5.9 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
17	Wicwas Lake-Marion CoveBelknap	No recent samples	6.9 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
18	Wicwas Lake-West CoveBelknap	No recent samples	6.3 µg/L	No recent samples	No recent samples	No recent samples	✓ Public
19	Crystal Lake-Deep SpotBelknap	No recent samples	11.1 µg/L	7 µg/L	No recent samples	No recent samples	Not recorded
20	Hawkins Pond-Deep SpotBelknap	No recent samples	17.5 µg/L	4.7 µg/L	No recent samples	No recent samples	Not recorded
21	Lake Winona-Chutes CoveBelknap	No recent samples	30 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
22	Pickerel Cove Upstream LakeBelknap	No recent samples	29 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
23	Shellcamp Pond-Deep SpotBelknap	No recent samples	17.7 µg/L	14.3 µg/L	No recent samples	No recent samples	Not recorded
24	Wicwas Lake-Bacteria SampleBelknap	No recent samples	28.9 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	Adams PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	Not recorded
	Bear Pond-Deep SpotBelknap	No recent samples	26.5 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	Brindle PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	15 ft	✓ Public
	Cawley PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10.5 ft	Not recorded
	Gillan PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Gilman PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	15 ft	Not recorded
	Halfmoon LakeBelknap	14.2 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	Huntress PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	20 ft	Not recorded
	Jackson PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	15 ft	Not recorded
	Knights PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Lake EileenBelknap	No recent samples	No recent samples	No recent samples	No recent samples	20 ft	Not recorded
	Lake Waukewan-Boat LaunchBelknap	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	Lake Winona-North Cove EastBelknap	No recent samples	9.6 µg/L	No recent samples	No recent samples	No recent samples	✓ Public
	Lily LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	5 ft	✓ Public
	Lily PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Little PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Locke LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	5 ft	Not recorded
	Lougee PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	40 ft	Not recorded
	Manning LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	55 ft	✓ Public
	Meadow Dam PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Meetinghouse PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Otter Pond-Deep SpotBelknap	No recent samples	13.6 µg/L	No recent samples	No recent samples	No recent samples	✓ Public
	Pickerel Cove Downstream LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Pickerel PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	24.9 ft	Not recorded
	Randlett PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Rollins PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	25 ft	✓ Public
	Round PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Saltmarsh PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	✓ Public
	Sargent LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	5 ft	Not recorded
	Spectacle PondBelknap	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	Not recorded
	Sunset LakeBelknap	No recent samples	No recent samples	No recent samples	No recent samples	60 ft	Not recorded

NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.

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Source: the New Hampshire Department of Environmental Services. See data sources.