Oldest Dams in Idaho

Idaho has 379 dams with recorded construction dates. The oldest dates to 1860 — 166 years ago. Idaho's earliest dams were built in the 19th century, an era of westward expansion, irrigation development, and early water infrastructure. Older dams require particular attention for safety, as many were built before modern engineering standards.

#	Dam	County	Year Built	Age	Height (ft)	Hazard	Condition
1	Johnson	Franklin	1860	166 yrs	28	Significant	Fair
2	Hawkins	Bannock	1870	156 yrs	35	Significant	Fair
3	Sheridan	Clark	1873	153 yrs	22	Significant	Poor
4	Mountain Home	Elmore	1884	142 yrs	48	High	Fair
5	Strong Arm No 1 (upper)	Franklin	1887	139 yrs	39	High	Fair
6	Little (north Crane Creek Dam)	Washington	1895	131 yrs	28	Significant	Fair
7	Little Valley	Bonneville	1897	129 yrs	23	Low	Fair
8	Strong Arm No 2 (lower)	Franklin	1897	129 yrs	27	Significant	Poor
9	Swan Falls	Ada	1901	125 yrs	88	High	Satisfactory
10	Orchard	Ada	1902	124 yrs	43	Significant	Poor
11	Hubbard Dam	Ada	1902	124 yrs	23	Low	Not Available
12	Boulder Lake	Valley	1902	124 yrs	15	Significant	Fair
13	Egin Canal Diversion	Fremont	1903	123 yrs	7	Low	Satisfactory
14	Barber	Ada	1904	122 yrs	26	Significant	Poor
15	Murtaugh Lake	Twin Falls	1905	121 yrs	42	High	Fair
16	Long Tom	Elmore	1906	120 yrs	60	Significant	Fair
17	Post Falls Middle Channel	Kootenai	1906	120 yrs	64	High	Satisfactory
18	Post Falls South Channel	Kootenai	1906	120 yrs	25	High	Satisfactory
19	Post Falls North Channel	Kootenai	1906	120 yrs	31	High	Fair
20	Minidoka Dam	Minidoka	1906	120 yrs	88	High	Not Available
21	Deep Creek Upper	Oneida	1906	120 yrs	36	Significant	Fair
22	Shoshone Falls Dam 3	Jerome	1907	119 yrs	15	Low	Satisfactory
23	Shoshone Falls Dam 2	Jerome	1907	119 yrs	16	Low	Satisfactory
24	Shoshone Falls Dam 1	Jerome	1907	119 yrs	16	Low	Satisfactory
25	Chilco	Kootenai	1907	119 yrs	17	Significant	Fair
26	Nelson	Latah	1907	119 yrs	17	Low	Satisfactory
27	Reservoir A Dam	Nez Perce	1907	119 yrs	61	High	Not Available
28	Shoshone Falls Dam 4	Twin Falls	1907	119 yrs	18	Low	Satisfactory
29	Boise River Diversion Dam	Ada	1908	118 yrs	68	High	Not Available
30	Mormon	Camas	1908	118 yrs	27	High	Fair
31	Deer Flat Lower Dam	Canyon	1908	118 yrs	49	High	Not Available
32	Little Crane Creek	Washington	1908	118 yrs	33	Low	Satisfactory
33	Wilson Lake	Jerome	1909	117 yrs	31	Significant	Fair
34	Alder	Owyhee	1909	117 yrs	21	Low	Poor
35	Grasmere South Dike	Owyhee	1909	117 yrs	11	Low	Fair
36	Lost Valley	Adams	1910	116 yrs	31	High	Poor
37	Magic Spillway	Blaine	1910	116 yrs	50	High	Fair
38	Blanchard Creek	Bonner	1910	116 yrs	19	Significant	Poor
39	Pioneer	Gooding	1910	116 yrs	15	Significant	Fair
40	Upper Bear Dam	Idaho	1910	116 yrs	13	Low	Not Rated
41	Hayden Lake	Kootenai	1910	116 yrs	13	Low	Fair
42	Winchester	Lewis	1910	116 yrs	40	High	Fair
43	Big Blue Creek	Owyhee	1910	116 yrs	34	Significant	Fair
44	Lodge Pond	Payette	1910	116 yrs	15	Significant	Fair
45	Deer Flat East Dike	Canyon	1911	115 yrs	18	Low	Not Available
46	Deer Flat Middle Dike	Canyon	1911	115 yrs	18	High	Not Available
47	Blackfoot	Caribou	1911	115 yrs	54	High	Fair
48	Paul	Clark	1911	115 yrs	28	Low	Poor
49	Curlew Valley	Oneida	1911	115 yrs	41	Significant	Poor
50	Salmon Falls	Twin Falls	1911	115 yrs	224	High	Fair

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