Largest Reservoirs in the United States

America's largest reservoirs hold staggering volumes of water — measured in acre-feet, where one acre-foot equals about 326,000 gallons, roughly enough to supply two households for a year. The biggest reservoirs serve as critical water supply, flood control, and hydroelectric infrastructure for entire regions.

Lake Mead behind Hoover Dam, Lake Sakakawea behind Garrison Dam, and Lake Oahe behind Oahe Dam are among the largest man-made reservoirs in the world. Their sheer size makes the dams that hold them some of the most consequential infrastructure in the country.

#	Dam	State	Max Storage (acre-ft)	Height (ft)	Purpose	Year
1	Soo Locks	Michigan	277,540,000	17	Navigation	1921
2	Hoover Dam	Nevada	30,237,000	730	Hydroelectric	1935
3	Garrison Dam - Williston Levee	North Dakota	26,000,000	28	Flood Risk Reduction	1953
4	Glen Canyon Dam	Arizona	25,025,826	710	Hydroelectric	1963
5	Oahe Dam - Fort Yates Flood Protection Project	South Dakota	23,600,000	245	Flood Risk Reduction	1966
6	Fort Peck Dam	Montana	19,100,000	256	Flood Risk Reduction	1940
7	Grand Coulee Dam	Washington	9,715,346	550	Flood Risk Reduction	1941
8	Herbert Hoover Dike - Ciz D	Florida	8,519,000	35	Flood Risk Reduction	1965
9	Kentucky Dam	Kentucky	7,535,400	206	Flood Risk Reduction	1944
10	Acorn Ridge	North Dakota	7,173,400	37	Flood Risk Reduction	2012
11	Sam Rayburn Dam	Texas	6,520,000	130	Flood Risk Reduction	1965
12	Fort Randall Dam	South Dakota	6,300,000	170	Flood Risk Reduction	1954
13	Wolf Creek Dam	Kentucky	6,089,000	258	Hydroelectric	1951
14	Libby Dam	Montana	6,027,000	422	Hydroelectric	1973
15	Bull Shoals Dam	Arkansas	5,408,000	282	Flood Risk Reduction	1951
16	Harry S. Truman Dam - Sterett Creek Dike	Missouri	5,202,000	98	Flood Risk Reduction	1978
17	Amistad Dam	Texas	5,128,000	287	Flood Risk Reduction	1969
18	Toledo Bend	Louisiana	5,097,500	135	Hydroelectric	1966
19	Painted Rock Dam - Saddle Dike 1	Arizona	4,831,500	181	Flood Risk Reduction	1960
20	Shasta Dam	California	4,661,860	602	Hydroelectric	1945
21	Flaming Gorge Dam	Utah	4,005,200	502	Flood Risk Reduction	1964
22	Eufaula Dam	Oklahoma	3,825,400	114	Flood Risk Reduction	1964
23	J. Strom Thurmond Dam	Georgia	3,820,000	200	Hydroelectric	1954
24	Spirit Lake Jetty 2	North Dakota	3,782,889	28	Flood Risk Reduction	1997
25	Blakely Mountain Dam	Arkansas	3,760,700	240	Flood Risk Reduction	1953
26	Hungry Horse Dam	Montana	3,588,000	564	Flood Risk Reduction	1953
27	Dworshak Dam	Idaho	3,560,000	717	Flood Risk Reduction	1973
28	Oroville	California	3,540,000	770	Flood Risk Reduction	1968
29	Table Rock Dam	Missouri	3,462,000	260	Flood Risk Reduction	1959
30	Hartwell Dam - Saddle Dike 1	Georgia	3,438,700	34	Hydroelectric	1962
31	Clemson Lower Diversion Dam - Saddle Dike	South Carolina	3,438,700	30	Flood Risk Reduction	1961
32	Clemson Upper Diversion Dam	South Carolina	3,438,700	75	Flood Risk Reduction	1961
33	Theodore Roosevelt Dam	Arizona	3,432,408	357	Hydroelectric	1911
34	Lower Red Lake Dam	Minnesota	3,428,000	17	Other	1931
35	Spirit Lake St. Michael 3	North Dakota	3,422,260	27	Flood Risk Reduction	1987
36	Norris Dam	Tennessee	3,363,168	265	Flood Risk Reduction	1936
37	Spirit Lake Jetty 1	North Dakota	3,341,785	22	Flood Risk Reduction	1997
38	Spirit Lake Bia 4 South	North Dakota	3,258,110	26	Flood Risk Reduction	1987
39	Mansfield Dam	Texas	3,223,000	278	Flood Risk Reduction	1942
40	Livingston	Texas	3,208,450	90	Hydroelectric	1969
41	Falcon Dam	Texas	3,177,000	175	Flood Risk Reduction	1953
42	Spirit Lake Bia 5	North Dakota	3,170,994	40	Flood Risk Reduction	1987
43	Spirit Lake Bia 4 North	North Dakota	3,170,994	38	Flood Risk Reduction	1987
44	Sardis Dam	Mississippi	3,016,000	117	Flood Risk Reduction	1940
45	New Melones Dam	California	2,870,000	625	Hydroelectric	1979
46	Greers Ferry Dam - Saddle Dike 2	Arkansas	2,844,000	72	Flood Risk Reduction	1962
47	Trinity Dam	California	2,760,870	538	Hydroelectric	1962
48	Grenada Dam	Mississippi	2,722,100	103	Flood Risk Reduction	1954
49	Bagnell	Missouri	2,677,000	148	Hydroelectric	1931
50	Spirit Lake St. Michael 2	North Dakota	2,673,067	32	Flood Risk Reduction	1987
51	Wright Patman Dam - Saddle Dike	Texas	2,650,000	33	Flood Risk Reduction	1953
52	Elephant Butte Dike	New Mexico	2,593,255	59	Flood Risk Reduction	1920
53	Buford Dam - Saddle Dike 3	Georgia	2,554,000	70		1958
54	John Day Lock And Dam	Oregon	2,530,000	230	Navigation	1968
55	Denison Dam - Platter Dike	Oklahoma	2,459,975	12	Flood Risk Reduction	1945
56	Spirit Lake Spring Lake	North Dakota	2,437,497	30	Flood Risk Reduction	1987
57	Spirit Lake St. Michael 1	North Dakota	2,437,497	22	Flood Risk Reduction	1987
58	Menasha Lock And Dam	Wisconsin	2,430,000	16	Flood Risk Reduction	1937
59	Sanford Dam	Texas	2,385,983	228	Recreation	1965
60	Don Pedro Dike A	California	2,300,000	25	Hydroelectric	1971
61	Tuttle Creek Dam - Blue Rapids Levee	Kansas	2,257,000	157	Flood Risk Reduction	1963
62	Lake George Outlet - Canal Intake	New York	2,250,000	28	Hydroelectric	1987
63	Saluda Backup Berm	South Carolina	2,200,000	213	Hydroelectric	2005
64	Pensacola	Oklahoma	2,197,000	155	Hydroelectric	1940
65	Whitney Dam - Kopperl Levee	Texas	2,100,400	166	Flood Risk Reduction	1951
66	Whitney Dam	Texas	2,100,400	166	Flood Risk Reduction	1951
67	Center Hill Dam	Tennessee	2,092,000	125	Flood Risk Reduction	1951
68	Barkley Lock And Dam	Kentucky	2,082,000	157	Navigation	1966
69	B.f. Sisk Dike	California	2,063,510	30	Hydroelectric	1967
70	Canyon Ferry Dam	Montana	2,051,000	225	Flood Risk Reduction	1954
71	Ferrells Bridge Dam	Texas	1,998,740	97	Flood Risk Reduction	1958
72	Navajo Dam	New Mexico	1,986,600	402	Flood Risk Reduction	1963
73	Norfork Dam	Arkansas	1,983,000	248	Flood Risk Reduction	1944
74	Beaver Dam - Saddle Dike 3	Arkansas	1,952,000	229	Flood Risk Reduction	1963
75	Ray Roberts Dam	Texas	1,931,900	141	Flood Risk Reduction	1986
76	Monticello Dam	California	1,902,086	304	Irrigation	1957
77	Kingsley	Nebraska	1,900,600	162	Hydroelectric	1941
78	Mossyrock	Washington	1,900,000	606	Hydroelectric	1968
79	Big Bend Dam	South Dakota	1,900,000	205	Flood Risk Reduction	1963
80	Belton Dam	Texas	1,876,700	192	Flood Risk Reduction	1954
81	Clarence Cannon Dam - Saddle Dam	Missouri	1,862,000	22	Flood Risk Reduction	1983
82	Millwood Dam - Okay Levee	Arkansas	1,854,930	91	Flood Risk Reduction	1966
83	Sugar Loaf Dam	Colorado	1,833,700	162	Irrigation	1968
84	Quabbin Spillway	Massachusetts	1,810,000	10	Water Supply	1938
85	Quabbin Winsor Dam	Massachusetts	1,810,000	170	Water Supply	1939
86	Quabbin Goodnough Dike	Massachusetts	1,810,000	135	Water Supply	1938
87	Lewisville Dam	Texas	1,804,300	135	Flood Risk Reduction	1955
88	Dale Hollow Dam	Tennessee	1,706,000	200	Flood Risk Reduction	1943
89	Cherokee Dam	Tennessee	1,699,431	175	Flood Risk Reduction	1941
90	Richland Creek Dam	Texas	1,686,587	96	Water Supply	1987
91	Stockton Dam	Missouri	1,674,000	153	Flood Risk Reduction	1969
92	Keystone Dam - Cleveland Levee	Oklahoma	1,672,613	34	Flood Risk Reduction	1964
93	American Falls Dam	Idaho	1,671,300	104	Flood Risk Reduction	1927
94	Lewis Smith	Alabama	1,670,600	300	Hydroelectric	1961
95	Iron Bridge Dam	Texas	1,660,023	85	Water Supply	1960
96	Douglas Dam	Tennessee	1,626,060	202	Flood Risk Reduction	1943
97	Martin	Alabama	1,622,000	168	Hydroelectric	1926
98	Broken Bow Dam - Reregulation Dam	Oklahoma	1,598,950	225	Flood Risk Reduction	1968
99	Davis Dam	Arizona	1,592,300	200	Hydroelectric	1950
100	Oologah Dam	Oklahoma	1,559,270	137	Flood Risk Reduction	1963