Largest Reservoirs in New Hampshire

New Hampshire has 660 dams with recorded storage capacity. The largest is Moore with 223,722 acre-feet of maximum storage. One acre-foot equals about 326,000 gallons — enough to supply roughly two households for a year.

#	Dam	County	Max Storage (acre-ft)	Height (ft)	Purpose	Year
1	Moore	Grafton	223,722	149	Hydroelectric	1957
2	Franklin Falls Dam	Merrimack	222,000	116	Flood Risk Reduction	1943
3	Lakeport	Belknap	165,800	10	Hydroelectric	1958
4	Murphy Dam	Coos	132,000	106	Recreation	1938
5	Everett Dam - Dike P-2	Hillsborough	131,000	30	Flood Risk Reduction	1961
6	Everett Dam - Dike P-1	Hillsborough	131,000	50	Flood Risk Reduction	1961
7	Everett Dam	Hillsborough	131,000	115	Flood Risk Reduction	1961
8	Hopkinton Dam - Dike H-3	Merrimack	131,000	66	Flood Risk Reduction	1962
9	Hopkinton Dam - Dike H-2	Merrimack	131,000	77	Flood Risk Reduction	1962
10	Hopkinton Dam	Merrimack	128,000	71	Flood Risk Reduction	1962
11	First Connecticut Lake Dam	Coos	114,000	56	Hydroelectric	1930
12	Blackwater Dam - Little Hill Dike	Merrimack	93,400	38	Flood Risk Reduction	1941
13	Blackwater Dam - Dodge Estate Dike	Merrimack	93,400	18	Flood Risk Reduction	1941
14	Blackwater Dam	Merrimack	93,400	75	Flood Risk Reduction	1941
15	Errol	Coos	80,000	25	Hydroelectric	1887
16	Wilder	Grafton	55,000	59	Hydroelectric	1950
17	Vernon	Cheshire	54,000	58	Hydroelectric	1909
18	Ossipee Lake Dam Headworks Dam	Carroll	47,200	12	Recreation	1919
19	Ossipee Lake Dam Berry Bay	Carroll	47,200	12	Recreation	1919
20	Massabesic Lake Dam	Hillsborough	46,375	30	Water Supply	1873
21	Surry Mountain Dam	Cheshire	44,000	83	Flood Risk Reduction	1941
22	Sunapee Lake Dam	Sullivan	40,900	14	Recreation	1872
23	Newfound Lake Dam	Grafton	40,000	12	Recreation	1840
24	Squam Lake	Grafton	39,600	17	Hydroelectric	1856
25	First Conn Lake South Bay Dike	Coos	38,950	14	Recreation
26	Lochmere	Belknap	33,280	11	Hydroelectric	1910
27	Comerford	Grafton	32,270	170	Hydroelectric	1930
28	Edward Macdowell Dam	Hillsborough	31,600	63	Flood Risk Reduction	1950
29	Bellows Falls	Cheshire	30,000	48	Hydroelectric	1907
30	Great East Lake Dam	Carroll	27,700	15	Recreation	1825
31	Otter Brook Dam	Cheshire	24,800	119	Flood Risk Reduction	1958
32	Big Dan Hole Pond Dam	Carroll	23,050	13	Recreation	1910
33	Bow Lake Dam	Strafford	22,380	24	Recreation	1832
34	Crescent Lake Dam	Carroll	21,320	15	Recreation	1854
35	Mascoma Lake Dam	Grafton	18,300	18	Recreation	1881
36	Lake Waukewan Dam	Belknap	15,900	15	Recreation	1880
37	Milton Three Ponds Dam	Strafford	15,000	19	Recreation	1824
38	Merrymeeting Lake Dam	Strafford	14,933	22	Recreation	1924
39	Conway Lake Dam	Carroll	14,784	17	Recreation	1763
40	Second Connecticut Lake Dam	Coos	12,500	28	Hydroelectric	1849
41	Jackman Reservoir Dam	Hillsborough	12,400	43	Hydroelectric	1926
42	Pawtuckaway Lake Dollof Dam	Rockingham	11,700	28	Recreation	1842
43	Pawtuckaway Lake /drowns Dam	Rockingham	11,700	18	Recreation	1842
44	Pawtuckaway Lake/gove Dike	Rockingham	11,700	9	Recreation	1842
45	Spofford Lake Dam	Cheshire	10,650	11	Recreation	1919
46	Ayers Island	Grafton	10,000	80	Hydroelectric	1924
47	Eastman Lake Dam	Sullivan	9,930	35	Recreation	1972
48	Goose Pond Dam	Grafton	9,635	31	Recreation	1918
49	Eastman Falls	Merrimack	9,340	43	Hydroelectric	1937
50	Pleasant Lake Dam	Merrimack	9,295	13	Recreation	1850

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