Hydroelectric Dams

2,099 dams in the US serve this purpose.

Dam Name	Hazard	Height	Built	Type	State
Oahe Dam Stanley	High Hazard	—	1966	Earth	South Dakota
Oakdale Carroll	High Hazard	58 ft	1925	Earth	Indiana
Oakland Susquehanna	Significant Hazard	18 ft	1896	Timber Crib	Pennsylvania
Oakland Kennebec	Low Hazard	14 ft	1901	Concrete	Maine
Oak Orchard Creek Dam Orleans	High Hazard	90 ft	1917	Concrete	New York
Occoquan Lower Storage Dam Fairfax	High Hazard	20 ft	—	Gravity	Virginia
Occum New London	Low Hazard	14 ft	1900	Masonry	Connecticut
Ocoee No. 1 Dam Polk	High Hazard	127 ft	1911	Concrete	Tennessee
Ocoee No. 2 Dam Polk	High Hazard	27 ft	1913	Timber Crib	Tennessee
Ocoee No. 3 Dam Polk	High Hazard	83 ft	1942	Concrete	Tennessee
Oconto Falls Lower Oconto	Low Hazard	22 ft	1857	Rockfill	Wisconsin
Oconto Falls Upper Oconto	High Hazard	35 ft	1902	Concrete	Wisconsin
Ogdensburg St. Lawrence	High Hazard	12 ft	1910	Gravity	New York
Old Falls York	Significant Hazard	36 ft	1890	Stone	Maine
Old Hickory Lock and Dam Davidson	High Hazard	—	1954	Concrete	Tennessee
Old River Concordia	High Hazard	134 ft	1990	Concrete	Louisiana
Olive Lake Grant	High Hazard	39 ft	1907	Earth	Oregon
Oliver Muscogee	High Hazard	69 ft	1959	Gravity	Georgia
Olympus Larimer	High Hazard	70 ft	1948	Earth	Colorado
Oneida Main Franklin	High Hazard	114 ft	1920	Concrete	Idaho
O'Neill Forebay Merced	High Hazard	88 ft	1967	Earth	California
Opal Springs Jefferson	Low Hazard	21 ft	1985	Rockfill	Oregon
Orono Penobscot	Low Hazard	15 ft	1917	Concrete	Maine
O'Shaughnessy Delaware	High Hazard	75 ft	1924	Gravity	Ohio
O`Shaughnessy Tuolumne	High Hazard	312 ft	1923	Gravity	California
Osullivan Grant	High Hazard	200 ft	1948	Earth	Washington
Oswego Lake Dam Clackamas	Significant Hazard	32 ft	1921	Concrete	Oregon
Otis Franklin	Low Hazard	19 ft	1898	Concrete	Maine
Otis Falls Hillsborough	Significant Hazard	27 ft	1982	Concrete	New Hampshire
Ottauquechee West Dam Windsor	Low Hazard	7 ft	1983	Concrete	Vermont
Otter Rapids Vilas	High Hazard	20 ft	1907	Gravity	Wisconsin
Ottumwa Wapello	Low Hazard	16 ft	1960	Gravity	Iowa
Our House Nevada	High Hazard	70 ft	1969	Concrete	California
Owens Dam Mariposa	High Hazard	72 ft	1949	Earth	California
Oxbow Adams	High Hazard	204 ft	1961	Rockfill	Oregon
Oxford Alexander	High Hazard	122 ft	1928	Gravity	North Carolina
Ozark Beach Taney	High Hazard	54 ft	1913	Buttress	Missouri
Ozark-Jetta Taylor Lock and Dam Franklin	Significant Hazard	42 ft	1969	Concrete	Arkansas
Pacificorp - Hunter Snow Lake Emery	Low Hazard	—	1978	Earth	Utah
Pacificorp - Sand Cove (Lower) Washington	Low Hazard	—	1928	Earth	Utah
Pacificorp - Sand Cove (Upper) Washington	Low Hazard	—	1928	Earth	Utah
Packwood Lake Lewis	High Hazard	14 ft	1964	Gravity	Washington
Paddy Creek Chute Spillway Burke	High Hazard	1 ft	1919	Concrete	North Carolina
Palisades Bonneville	High Hazard	270 ft	1957	Earth	Idaho
Palmer Falls Warren	Low Hazard	37 ft	1913	Concrete	New York
Panasuk Dam Roosevelt	Significant Hazard	57 ft	—	Earth	Montana
Paper Mill Hillsborough	Low Hazard	9 ft	1922	Concrete	New Hampshire
Pardeeville Columbia	High Hazard	16 ft	1849	Gravity	Wisconsin
Paris Douglas	High Hazard	51 ft	1963	Earth	Oregon
Parishville St. Lawrence	Low Hazard	19 ft	1925	Gravity	New York