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07 – Anderson Ranch Dam

Anderson Ranch Dam is an earth and rockfill dam located on the South Fork of the Boise River in Elmore County, Idaho. Standing at 456 feet tall and 1,350 feet long, it was the tallest dam of its type in the world upon its completion in 1950. The dam creates Anderson Ranch Reservoir, which has a total capacity of 503,500 acre-feet and a surface area of 4,815 acres. Its primary purpose is to provide irrigation water for agriculture, with hydroelectric power generation as a secondary function. The powerplant, commissioned in 1951 and upgraded in 1986, has an installed capacity of 40 megawatts.​Wikipedia+3Wikipedia+3Wikipedia+3

Construction began in 1941 but faced delays due to material, fuel, and labor shortages during World War II, including a nine-month halt starting in December 1942. In 1943, Japanese American internees from the Minidoka War Relocation Center were employed to address labor shortages. Currently, the U.S. Bureau of Reclamation and the Idaho Water Resource Board are collaborating on a project to raise the dam by six feet, which will increase storage capacity by approximately 29,000 acre-feet; the design phase is scheduled for completion in summer 2024.​

More Information

https://en.wikipedia.org/wiki/Anderson_Ranch_Dam


Coordinates: 43.357478, -115.448645
Elevation: 4239 ft
Difficulty: 2
What to Expect: No info

[reblex id=’779′]

Check In

Use the form below to check in. Check-ins must include a photo of you or your bike at the challenge site with the 2025 bandanna. All participants must be registered IAMC Challenge Members. Leave a description of your ride and share road conditions — snow, water, obstacles, and tips for future riders are all appreciated.

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The stated difficulty is an estimate. Rating your experience helps future riders stay safe. You alone are responsible for the safety of your ride.

Check-Ins are Closed for the 2025 Challenge.

17 Check-Ins

December 31, 2025 2:59 pm
Bike: Royal Enfield Himalayan
Difficulty: 1 / 5

My Uncle used to work here for 20 years. Crazy that he would drive here in the winter.

Check-in photo
November 23, 2025 9:22 am
Bike: F800 GSA
Difficulty: 1 / 5

Great fishing in the south fork below the dam. Always a fun ride out this way.

Check-in photo
November 8, 2025 7:46 pm
Bike: 23' KLR 650
Difficulty: 1 / 5

Came from Long Tom got a bit lost trying to find a back way in ended up just coming back to the main road. (Forgot my bandana, willing to provide a DNA sample upon request.)

Check-in photo
November 2, 2025 9:04 am
Bike: DR650
Difficulty: 1 / 5

Went through Prairie to site 2 of 3 day. Little bit of snow higher up. Nov.1

Check-in photo
August 26, 2025 7:47 am
Bike: beta 390 RRS
Difficulty: 2 / 5

Start of my trinity run, but a nice spot to stop.

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July 28, 2025 9:59 pm
Bike: Yamaha tenere 700
Difficulty: 2 / 5

May 3rd. Sam's Poker Run. Nice day, not a lot of dust

Check-in photo
May 28, 2025 5:32 pm
Bike: BMW R1250GSA
Difficulty: 2 / 5

Not much to say.....it's a big dam.

Check-in photoCheck-in photo
May 10, 2025 12:32 pm
Bike: KLR 650
Difficulty: 2 / 5

Last stop of the day. Some good fishing spots to check out below the damn.

Check-in photo
May 4, 2025 10:46 am
Bike: DR650
Difficulty: 2 / 5

Last stop on the Prairie Poker Run! Absolutely beautiful spot. Would've loved to stick around and check out the place, if I wasn't in dire need of a Y-Stop burger, haha.

Check-in photo
May 4, 2025 9:13 am
Bike: 990
Difficulty: 2 / 5

Great ride yesterday. 8 sites three were repeats

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May 3, 2025 7:39 pm
Bike: KTM 890
Difficulty: 2 / 5

Great route. Good food at the Y Stop in Prairie. The store said they sell gas but they were out.

Check-in photo
May 3, 2025 6:41 pm
Bike: KTM 890
Difficulty: 2 / 5

good times, great day for a ride

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May 3, 2025 5:49 pm
Bike: DR650
Difficulty: 1 / 5

Nice sunny day for the group ride.

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May 3, 2025 5:20 pm
Bike: R1200GS
Difficulty: 2 / 5

I have always had the urge to ride down the spillway.

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April 16, 2025 5:28 pm
Bike: 690 EnduroR
Difficulty: 1 / 5

A nice gravel/dirt road off of Hwy 20, beautiful dam view awaits you.

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April 15, 2025 9:06 pm
Bike: BMW R1200GSA
Difficulty: 1 / 5

Pretty cool. Never been here before. Looks like the gravel road is brand new or freshly touched up. Hardly a bump.

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April 12, 2025 4:37 pm
Bike: 2003 Suzuki DR650
Difficulty: 2 / 5

3rd site for the day. Lots of fishermen out this morning.

Check-in photo
Check-Ins are Closed for the 2025 Challenge.

17 thoughts on “07 – Anderson Ranch Dam”

  1. Came from Long Tom got a bit lost trying to find a back way in ended up just coming back to the main road. (Forgot my bandana, willing to provide a DNA sample upon request.)

  2. Last stop on the Prairie Poker Run! Absolutely beautiful spot. Would’ve loved to stick around and check out the place, if I wasn’t in dire need of a Y-Stop burger, haha.

  3. Great route. Good food at the Y Stop in Prairie. The store said they sell gas but they were out.

  4. Pretty cool. Never been here before. Looks like the gravel road is brand new or freshly touched up. Hardly a bump.

Comments are closed.