Largest Reservoirs in Idaho

Idaho has 69 dams with recorded storage capacity. The largest is Dworshak Dam with 3,560,000 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	Dworshak Dam	Clearwater	3,560,000	717	Flood Risk Reduction	1973
2	American Falls Dam	Power	1,671,300	104	Flood Risk Reduction	1927
3	Palisades Dam	Bonneville	1,417,810	270	Flood Risk Reduction	1957
4	Albeni Falls Dam	Bonner	1,155,000	180	Hydroelectric	1955
5	Cascade Dam	Valley	693,200	110	Hydroelectric	1948
6	Blackfoot	Caribou	543,500	54	Irrigation	1911
7	Anderson Ranch Dam	Elmore	474,942	456	Flood Risk Reduction	1950
8	China Hat Dike	Caribou	388,390	29	Irrigation	1923
9	Lucky Peak Dam	Ada	307,043	340	Flood Risk Reduction	1955
10	Arrowrock Dam	Boise	272,224	350	Flood Risk Reduction	1915
11	C J Strike	Owyhee	250,000	115	Hydroelectric	1952
12	Minidoka Dam	Minidoka	220,200	88	Fish and Wildlife Pond	1906
13	Magic Spillway	Blaine	195,000	50	Hydroelectric	1910
14	Hells Canyon	Adams	188,000	330	Hydroelectric	1967
15	Island Park Dike	Fremont	169,646	12		1938
16	Deer Flat Lower Dam	Canyon	159,365	49	Irrigation	1908
17	Deer Flat East Dike	Canyon	159,000	18	Irrigation	1911
18	Deer Flat Middle Dike	Canyon	159,000	18	Irrigation	1911
19	Deadwood Dam	Valley	153,992	165	Hydroelectric	1931
20	Cabinet Gorge	Bonner	104,600	177	Hydroelectric	1952
21	Ririe Dam	Bonneville	100,500	253	Flood Risk Reduction	1977
22	Milner S Embankment	Twin Falls	39,000	65	Irrigation	1992
23	Little Wood River Dam	Blaine	33,300	129	Irrigation	1939
24	Black Canyon Diversion Dam	Gem	31,200	183	Hydroelectric	1924
25	Oneida Embankment	Franklin	19,000	60	Irrigation	1921
26	Oneida Main	Franklin	19,000	114	Irrigation	1920
27	Soda	Caribou	16,300	103	Irrigation	1925
28	Mann Creek Dam	Washington	12,536	148	Irrigation	1967
29	Lower Salmon	Gooding	10,900	110	Hydroelectric	1949
30	Ashton	Fremont	9,900	65	Irrigation	1917
31	Bliss	Gooding	8,415	140	Hydroelectric	1950
32	Mountain View Dam	Owyhee	7,818	25	Irrigation	1969
33	Gem State	Bonneville	6,700	40	Hydroelectric	1988
34	Gem State Left Dike	Bonneville	6,700	30	Hydroelectric	1988
35	Gem State Right Dike	Bonneville	6,700	30	Hydroelectric	1988
36	Equalizer	Bingham	6,300	23	Irrigation	1937
37	Wilson Lake	Jerome	4,600	31	Irrigation	1909
38	Hubbard Dam	Ada	4,060	23	Irrigation	1902
39	Reservoir A Dam	Nez Perce	3,665	61	Irrigation	1907
40	Soldiers Meadow Dam	Nez Perce	3,195	69	Irrigation	1922
41	Osburn	Shoshone	1,800	71	Tailings
42	Shoshone Falls Dam 3	Jerome	1,500	15	Hydroelectric	1907
43	Shoshone Falls Dam 2	Jerome	1,500	16	Hydroelectric	1907
44	Shoshone Falls Dam 1	Jerome	1,500	16	Hydroelectric	1907
45	Shoshone Falls Dam 4	Twin Falls	1,500	18	Hydroelectric	1907
46	Upper Dike	Bonneville	1,230	12	Hydroelectric	1982
47	Upper Diversion Dam #2	Bonneville	1,230	33	Hydroelectric	1982
48	City Diversion	Bonneville	1,200	30	Hydroelectric	1982
49	Lower Diversion	Bonneville	1,200	14	Hydroelectric	1982
50	Grace Dike	Caribou	1,100	10	Irrigation

← All dams in Idaho · Largest reservoirs nationwide