Longest Dams Length Comparison (KM Crest)
Compare the 10 longest dams by crest length with dykes, from Hirakud at 25.8 km to Sanmenxia at 1.1. Lengths in km and miles with authority sources listed.
Visual comparison
All values
Click any row to load it as Entry A.
| Name | Value | Context | Source |
|---|---|---|---|
| Hirakud Dam Longest dam in the world with dykes. | 25.8 kilometers | Odisha, India, earthen dykes total | Hirakud authority spec: 25.8 km total length |
| Fort Peck Dam Longest in the United States. | 6.4 kilometers | Montana, USA, hydraulic fill | USACE Fort Peck spec: 6.4 km crest length |
| Gardiner Dam 1.4 under Fort Peck. | 5 kilometers | Saskatchewan, Canada, embankment | Saskatchewan authority spec: Gardiner 5.0 km |
| Aswan High Dam Nile anchor. | 3.8 kilometers | Aswan, Egypt, rockfill | Egyptian authority Aswan spec: 3.8 km crest length |
| Mangla Dam Ranks above Tarbela; see notes on order. | 3.1 kilometers | Azad Kashmir, Pakistan, embankment | Mangla authority spec: 3.1 km crest length |
| Tarbela Dam Tall fill dam kept for scale here. | 3 kilometers | Khyber Pakhtunkhwa, Pakistan, kept for scale | Tarbela authority spec: 3.0 km embankment |
| Oahe Dam Missouri River anchor. | 2.8 kilometers | South Dakota, USA, rolled earth | USACE Oahe spec: 2.8 km crest length |
| Ataturk Dam Euphrates anchor. | 1.7 kilometers | Anatolia, Turkey, rockfill | Turkish DSI Ataturk spec: 1.7 km crest length |
| Nagarjuna Sagar Dam Largest masonry dam here. | 1.6 kilometers | Telangana, India, masonry | Nagarjuna authority spec: 1.6 km crest length |
| Sanmenxia Dam Shortest row here. | 1.1 kilometers | Henan, China, concrete gravity | Yellow River authority Sanmenxia spec: 1.1 km |
About this converter
Hirakud runs 25.8 km total with dykes, about four times Fort Peck at 6.4. Gardiner at 5.0, Aswan at 3.8, Mangla at 3.1, Tarbela at 3.0 for scale, Oahe at 2.8, Ataturk at 1.7, Nagarjuna Sagar at 1.6 and Sanmenxia at 1.1 follow. Lengths count dam crest with dykes where authorities include them. Hirakud main dam alone runs far shorter, so dyke counting explains its lead and is flagged. Heights rank on a separate dam page, so towers stay out here.
How to use it
Pick two dams and a unit in the top row. The three boxes below stay linked. Change any box and the other two update. Try Hirakud against Fort Peck to see the four times gap. The bars below scale to Hirakud so Sanmenxia looks thin next to it. Switch the unit to miles for US figures. Ratios are exact divisions of the crest lengths.
Mangla at 3.1 ranks above Tarbela at 3.0 despite draft table quirks. Tarbela 3.0 is kept for scale as a tall fill dam against long embankments. Hirakud 25.8 counts main plus dykes per authority spec. Figures follow dam authority crest specs. Lengths differ from heights, so dam-height-comparison ranks separately.
FAQ
What is the longest dam?
Hirakud at 25.8 km total with dykes. Fort Peck follows at 6.4 km.
Is this the same as dam heights?
No. Heights rank elsewhere. This page keeps crest lengths only.
Why is Tarbela listed at 3.0?
For scale. A tall fill dam against long embankment dams.
Does Hirakud count dykes?
Yes per authority spec. Main dam alone runs far shorter.
Sources
- Dam authority crest specs: Hirakud 25.8 with dykes; Fort Peck 6.4; Gardiner 5.0; Aswan 3.8; Mangla 3.1; Tarbela 3.0 scale; Oahe 2.8; Ataturk 1.7; Nagarjuna Sagar 1.6; Sanmenxia 1.1 km crest
Last verified: 2026-10-09 · 10 entries
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