The Euphrates River runs 1,700 miles from the mountains of eastern Turkey to the Persian Gulf.
Notes on verification
Multiple independent tertiary sources corroborate the ~1,700-mile length and the geography (source in eastern Turkey's mountains, mouth at Persian Gulf), though exact figures vary slightly (1,678-1,740 miles) due to measurement methodology differences, which is typical for river-length claims.
Sources
- What Does the Future of the Euphrates Spell for the Middle East? (smithsonianmag.com)
- https://www.dictionary.com/browse/euphrates (dictionary.com)
- https://web.bryant.edu/~langlois/ecology/euphrates.htm (web.bryant.edu)
- https://www.diy.org/article/euphrates (diy.org)
- https://www.sheppardsoftware.com/Middleeastweb/factfile/Unique-facts-MiddleEast3.htm (sheppardsoftware.com)