Largest Reservoirs in Montana

Montana has 2960 dams with recorded storage capacity. The largest is Fort Peck Dam with 19,100,000 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	Fort Peck Dam	McCone	19,100,000	256	Flood Risk Reduction	1940
2	Libby Dam	Lincoln	6,027,000	422	Hydroelectric	1973
3	Hungry Horse Dam	Flathead	3,588,000	564	Flood Risk Reduction	1953
4	Canyon Ferry Dam	Lewis and Clark	2,051,000	225	Flood Risk Reduction	1954
5	Tiber Dike	Liberty	1,424,478	65		1956
6	Yellowtail Dam	Big Horn	1,331,725	525		1966
7	Hebgen Dam	Gallatin	525,620	120	Hydroelectric	1915
8	Noxon Rapids	Sanders	400,000	260	Hydroelectric	1960
9	Clark Canyon Dam	Beaverhead	328,979	148	Flood Risk Reduction	1964
10	Holter Dam	Lewis and Clark	306,000	124	Hydroelectric	1918
11	Fresno Dam	Hill	229,288	111	Irrigation	1939
12	Hauser Dam	Lewis and Clark	139,890	125	Hydroelectric	1911
13	Lake Frances North Dam	Pondera	133,619	22	Irrigation	1909
14	Lake Frances East Dam	Pondera	133,619	59	Irrigation	1909
15	Lima	Beaverhead	133,000	56	Irrigation	1934
16	Tongue River Dam	Big Horn	127,655	93	Irrigation	1939
17	Gibson Dam	Teton	121,981	199	Irrigation	1929
18	Lake Sherburne Dam	Glacier	110,679	109	Irrigation	1919
19	Bynum Reservoir Dam	Teton	107,000	60	Irrigation	1926
20	Deadmans Basin Dam	Wheatland	100,000	60	Irrigation	1941
21	Nelson Dike Da	Phillips	79,224	28	Irrigation	1915
22	Georgetown Dam	Deer Lodge	77,500	55	Hydroelectric	1900
23	Medicine Lake Dam No. 4	Sheridan	67,100	15	Fish and Wildlife Pond	1935
24	Ruby Dam	Madison	56,355	111	Irrigation	1938
25	Pishkun Dike 7	Teton	46,670	16	Irrigation	1931
26	West Fork Bitterroot (painted Rocks)	Ravalli	45,100	143	Irrigation	1940
27	Madison Dam	Madison	42,053	39	Hydroelectric	1907
28	Como Dam	Ravalli	40,700	76	Irrigation	1910
29	Willow Creek Bor Mt-dike 3	Lewis and Clark	39,800	3		1941
30	Martinsdale, East Dam	Wheatland	38,958	49	Irrigation	1939
31	Martinsdale, North Dam	Wheatland	38,958	91	Irrigation	1939
32	Swift (pondera)	Pondera	34,000	205	Irrigation	1967
33	Swift Dike (pondera)	Pondera	34,000	53	Irrigation	1967
34	Deadmans Basin Dike	Wheatland	34,000	23	Irrigation	1941
35	Four Horns	Glacier	33,724	50	Irrigation	1915
36	Willow Creek	Big Horn	31,710	136	Irrigation	1941
37	Cooney	Carbon	28,230	102	Irrigation	1937
38	Ashley	Flathead	27,600	10	Irrigation	1928
39	Lower Two Medicine	Glacier	27,050	70	Irrigation	1967
40	Willow Creek Dam	Madison	26,600	105	Irrigation	1938
41	Thompson Falls - Intake Dam A	Sanders	24,450	62	Hydroelectric	1915
42	Ninepipe	Lake	23,370	41	Irrigation	1911
43	Weigand Reservoir East	Phillips	21,558	21
44	Whitetail Dam	Jefferson	21,400	28	Irrigation	1922
45	Weigand Reservoir	Blaine	21,378	13
46	Mystic Dike	Stillwater	21,000	21	Hydroelectric	1927
47	Silver Lake West Dam	Deer Lodge	17,920	17	Irrigation	1918
48	Silver Lake East Dam	Deer Lodge	17,920	11	Irrigation	1918
49	Pablo North Dike	Lake	16,700	5	Irrigation	1912
50	Nevada Creek Dam	Powell	15,903	105	Irrigation	1938

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