Dams in Idaho

394 damsAvg age: 76 years

High Hazard

141

Significant

156

Low Hazard

Dam Safety in Idaho

Idaho has 394 dams tracked in the National Inventory of Dams. Of these, 96 (24%) are classified as high hazard — meaning failure would probably cause loss of human life — and 141 are classified as significant hazard. Currently, 41 dams in the state have a condition assessment of poor or unsatisfactory, indicating recognized safety deficiencies.

The average dam in Idaho is 76 years old. As dams age, inspection frequency and maintenance become increasingly important for ensuring public safety. The most common purpose for dams in Idaho is irrigation, accounting for 184 of the state's dams.

The federal inventory is not every dam in Idaho. It includes dams rated high or significant hazard, plus low-hazard dams above a size threshold (taller than 25 feet holding more than 15 acre-feet, or taller than 6 feet holding more than 50 acre-feet). Small, older dams below that line are usually left out, even though they can still shape the streams around them. The state's own dam safety program often tracks many more, and it is the agency that inspects most of them.

Use the search above to find dams near any address in Idaho, or browse by county below. Each dam listing includes its hazard potential classification, condition assessment, physical characteristics, and inspection history from the NID.

Idaho Dam Facts

Total Dams	394
High Hazard Dams	96
Average Dam Age	76 years
Tallest Dam	789 ft
Largest Reservoir	3,560,000 acre-ft
Poor/Unsatisfactory Condition	41

Notable Dams in Idaho

Thompson Mtis789 ftHigh Dworshak Dam717 ftHigh Anderson Ranch Dam456 ftHigh Arrowrock Dam350 ftHigh Lucky Peak Dam340 ftHigh

Explore Idaho Dams

Oldest DamsEarliest dams in Idaho Tallest DamsHighest dams in Idaho

Counties in Idaho

Ada16 dams4 high hazard Adams8 dams6 high hazard Bannock4 dams1 high hazard Bear Lake6 dams1 high hazard Bingham2 dams1 high hazard Blaine8 dams4 high hazard Boise2 dams1 high hazard Bonner6 dams2 high hazard Bonneville14 dams6 high hazard Boundary3 dams2 high hazard Camas4 dams1 high hazard Canyon3 dams2 high hazard Caribou19 dams6 high hazard Cassia6 dams2 high hazard Clark2 dams Clearwater5 dams1 high hazard Custer15 dams2 high hazard Elmore18 dams3 high hazard Franklin21 dams8 high hazard Fremont15 dams3 high hazard Gem7 dams2 high hazard Gooding9 dams2 high hazard Idaho3 dams Jerome5 dams Kootenai9 dams3 high hazard Latah4 dams1 high hazard Lemhi13 dams Lewis1 dams1 high hazard Madison1 dams Minidoka1 dams1 high hazard Nez Perce4 dams2 high hazard Oneida10 dams6 high hazard Owyhee50 dams4 high hazard Payette7 dams1 high hazard Power3 dams1 high hazard Shoshone7 dams3 high hazard Twin Falls18 dams4 high hazard Valley41 dams4 high hazard Washington24 dams5 high hazard

High Hazard Dams in Idaho

Dam	County	Height	Condition	Purpose
Thompson Mtis	Custer	789 ft	Fair	Tailings
Dworshak Dam	Clearwater	717 ft	Not assessed	Flood Risk Reduction
Anderson Ranch Dam	Elmore	456 ft	Not assessed	Flood Risk Reduction
Arrowrock Dam	Boise	350 ft	Not assessed	Flood Risk Reduction
Lucky Peak Dam	Ada	340 ft	Not assessed	Flood Risk Reduction
Hells Canyon	Adams	330 ft	Satisfactory	Hydroelectric
Palisades Dam	Bonneville	270 ft	Not assessed	Flood Risk Reduction
Ririe Dam	Bonneville	253 ft	Not assessed	Flood Risk Reduction
Salmon Falls	Twin Falls	224 ft	Fair	Other
Oxbow	Adams	209 ft	Fair	Hydroelectric
Black Canyon Diversion Dam	Gem	183 ft	Not assessed	Hydroelectric
Albeni Falls Dam	Bonner	180 ft	Not assessed	Hydroelectric
Cabinet Gorge	Bonner	177 ft	Satisfactory	Hydroelectric
Deadwood Dam	Valley	165 ft	Not assessed	Hydroelectric
Mann Creek Dam	Washington	148 ft	Not assessed	Irrigation
Oakley	Cassia	145 ft	Fair	Irrigation
Bliss	Gooding	140 ft	Satisfactory	Hydroelectric
Lucky Friday No 4	Shoshone	132 ft	Satisfactory	Tailings
Little Wood River Dam	Blaine	129 ft	Not assessed	Irrigation
Texas Basin	Owyhee	121 ft	Fair	Irrigation
C J Strike	Owyhee	115 ft	Satisfactory	Hydroelectric
Oneida Main	Franklin	114 ft	Fair	Irrigation
Lower Salmon	Gooding	110 ft	Satisfactory	Hydroelectric
Cascade Dam	Valley	110 ft	Not assessed	Hydroelectric
American Falls Dam	Power	104 ft	Not assessed	Flood Risk Reduction
Soda	Caribou	103 ft	Fair	Irrigation
Hulet	Owyhee	99 ft	Fair	Other
Daniels	Oneida	96 ft	Fair	Irrigation
Fish Creek	Blaine	92 ft	Poor	Irrigation
Moyie	Boundary	92 ft	Fair	Hydroelectric
Deep Creek	Oneida	91 ft	Fair	Other
Crowther	Oneida	90 ft	Fair	Irrigation
Cedar Creek	Twin Falls	90 ft	Fair	Irrigation
Minidoka Dam	Minidoka	88 ft	Not assessed	Fish and Wildlife Pond
Swan Falls	Ada	88 ft	Satisfactory	Hydroelectric
Devil Creek	Oneida	84 ft	Fair	Irrigation
Montpelier Creek	Bear Lake	82 ft	Fair	Other
Fairchild No. 1 (upper)	Washington	78 ft	Fair	Irrigation
Aikman	Gem	77 ft	Fair	Irrigation
Mackay	Custer	75 ft	Fair	Other
Glendale	Franklin	73 ft	Fair	Other
Osburn	Shoshone	71 ft	Fair	Tailings
Foster	Franklin	70 ft	Fair	Irrigation
Soldiers Meadow Dam	Nez Perce	69 ft	Not assessed	Irrigation
Lamont	Franklin	68 ft	Fair	Irrigation
Dry Creek Main	Payette	68 ft	Fair	Irrigation
Boise River Diversion Dam	Ada	68 ft	Not assessed	Irrigation
Milner S Embankment	Twin Falls	65 ft	Satisfactory	Irrigation
Ashton	Fremont	65 ft	Satisfactory	Irrigation
Post Falls Middle Channel	Kootenai	64 ft	Satisfactory	Hydroelectric
Crane Creek Main Dam	Washington	64 ft	Fair	Other
Brundage	Adams	63 ft	Fair	Other
Squaw Creek	Owyhee	61 ft	Fair	Irrigation
C Ben Ross	Adams	61 ft	Fair	Other
Reservoir a Dam	Nez Perce	61 ft	Not assessed	Irrigation
Oneida Embankment	Franklin	60 ft	Fair	Irrigation
J-ditch Effluent Lagoon	Valley	60 ft	Fair	Other
Portneuf	Caribou	55 ft	Fair	Other
Blackfoot	Caribou	54 ft	Fair	Irrigation
Blacks Creek	Ada	52 ft	Fair	Other
Magic Spillway	Blaine	50 ft	Fair	Hydroelectric
Paddock Valley	Washington	49 ft	Fair	Irrigation
Deer Flat Lower Dam	Canyon	49 ft	Not assessed	Irrigation
Sublett	Cassia	48 ft	Fair	Irrigation
Mountain Home	Elmore	48 ft	Fair	Other
Spring Valley	Latah	47 ft	Fair	Other
Saint John	Oneida	43 ft	Unsatisfactory	Irrigation
Weston	Oneida	42 ft	Fair	Other
Murtaugh Lake	Twin Falls	42 ft	Fair	Irrigation
Hot Springs No 2	Elmore	41 ft	Fair	Irrigation
Winchester	Lewis	40 ft	Fair	Other
Gem State	Bonneville	40 ft	Satisfactory	Hydroelectric
Simplot Effluent Irrigation Lagoon	Bannock	39 ft	Fair	Irrigation
Strong Arm No 1 (upper)	Franklin	39 ft	Fair	Other
Twin Lakes South	Franklin	36 ft	Satisfactory	Irrigation
Soda Creek Main Dam	Caribou	36 ft	Fair	Other
Star No 6	Shoshone	33 ft	Fair	Tailings
Twin Lakes North	Franklin	32 ft	Fair	Irrigation
Lost Valley	Adams	31 ft	Poor	Other
Post Falls North Channel	Kootenai	31 ft	Fair	Hydroelectric
Gem State Left Dike	Bonneville	30 ft	Satisfactory	Hydroelectric
Gem State Right Dike	Bonneville	30 ft	Satisfactory	Hydroelectric
China Hat Dike	Caribou	29 ft	Satisfactory	Irrigation
Goose Lake	Adams	27 ft	Fair	Irrigation
Mormon	Camas	27 ft	Fair	Other
Crane Creek Dike	Washington	25 ft	Fair	Other
Henrys Lake	Fremont	25 ft	Fair	Other
Post Falls South Channel	Kootenai	25 ft	Satisfactory	Hydroelectric
Little Payette Lake Main	Valley	25 ft	Fair	Irrigation
Trail Creek Dam	Blaine	23 ft	Fair	Other
Equalizer	Bingham	23 ft	Fair	Irrigation
Itafos Cooling Pond	Caribou	20 ft	Satisfactory	Other
Mcarthur	Boundary	19 ft	Fair	Other
Deer Flat Middle Dike	Canyon	18 ft	Not assessed	Irrigation
Upper Dike	Bonneville	12 ft	Satisfactory	Hydroelectric
Island Park Dike	Fremont	12 ft	Not assessed