This list covers 26 rivers with names starting with the letter U, running alphabetically from “Ucayali” to “Uzen (Great Uzen).” They range from short cultural waterways to major international rivers thousands of kilometers long, crossing deserts, mountains, and rainforests. People rely on them for drinking water, irrigation, fishing, hydroelectric power, transportation, and recreation like rafting and kayaking.

Rivers are natural channels of flowing water that carry rain, snowmelt, and groundwater from higher ground down to lakes, seas, or other rivers. Many have shaped human history along their banks, such as the Ugra in Russia, where a 1480 standoff known as the “Great Stand” helped end Mongol rule over Muscovy. Others, like the Uji in Japan, are woven into literature and local tradition.

Below you’ll find the table with River, Countries, Length (km), Type, and Description.

River: the name of each river, so you can quickly find the one you’re looking for or spot familiar names in the list.

Countries: the country or countries each river flows through, helping you place it on a map and understand its regional importance.

Length (km): the river’s total length in kilometers, giving you a quick sense of its scale compared to others on the list.

Type: whether the river is a main river, a tributary, or an ephemeral (seasonal) river, so you know how it fits into a larger water system.

Description: a short summary of what makes the river notable, from its geography to its history and culture, so you get useful context at a glance.

Rivers

RiverCountriesLength (km)Type
UcayaliPeru1,771Tributary river
UgabNamibia400Ephemeral river
UgraRussia399Tributary river
UjiJapan21River
UkhtaRussia138River
UllaSpain132River
UluaHonduras250River
UmatillaUnited States143Tributary river
UmbaRussia120River
Ume (Umeälven)Sweden460River
UmgeniSouth Africa232River
UmpquaUnited States179River
UmzimvubuSouth Africa200River
UnaBosnia and Herzegovina, Croatia212Tributary river
UnareVenezuela315River
UnstrutGermany192Tributary river
UpaRussia345Tributary river
UralRussia, Kazakhstan2,428River
UreEngland129River
UrubambaPeru863Tributary river
UruguayBrazil, Argentina, Uruguay1,838River
UskWales122River
UssuriRussia, China897Tributary river
UsumacintaMexico, Guatemala1,000River
UvacSerbia, Bosnia and Herzegovina125Tributary river
Uzen (Great Uzen)Kazakhstan400River

Descriptions

Ucayali
One of the main sources of the Amazon, formed by the union of the Apurímac and Urubamba rivers in the Peruvian Andes before flowing into the Amazon Basin.
Ugab
A seasonal desert river that usually flows only underground or after rare rains, cutting through Namibia’s arid landscape toward the Atlantic coast.
Ugra
A right tributary of the Oka River, historically significant as the site of the 1480 “Great Stand” that ended Mongol rule over Muscovy.
Uji
A short but culturally important river near Kyoto, celebrated in classical literature including “The Tale of Genji” and known for its tea-growing region.
Ukhta
A river in northern Russia’s Komi Republic that gives its name to the nearby oil-industry city of Ukhta.
Ulla
A river in Galicia that winds through green countryside before reaching the Atlantic, valued locally for fishing and scenic river towns.
Ulua
One of Honduras’s principal rivers, flowing through a fertile valley important for agriculture before emptying into the Caribbean Sea.
Umatilla
A river in Oregon that joins the Columbia River, giving its name to a nearby city, county, and Native American reservation.
Umba
A river on the Kola Peninsula known for salmon fishing, flowing into the White Sea near the village that shares its name.
Ume (Umeälven)
A major Swedish river valued for hydroelectric power, flowing from the mountains near Norway down to the Gulf of Bothnia at Umeå.
Umgeni
A river in KwaZulu-Natal that flows past Durban, supplying drinking water to the region and featuring the scenic Howick Falls.
Umpqua
An Oregon river known for excellent steelhead and salmon fishing, flowing from the Cascade Range through forested valleys to the Pacific Ocean.
Umzimvubu
A river in the Eastern Cape whose name means “home of the hippopotamus,” carving dramatic gorges before reaching the Indian Ocean.
Una
Famous for its turquoise, waterfall-studded waters, this river is a popular rafting and kayaking destination along the two countries’ border.
Unare
A river in northeastern Venezuela that flows through savanna plains into the Caribbean Sea, important for regional agriculture.
Unstrut
A gentle river in Thuringia and Saxony-Anhalt known for vineyards along its banks and canoe tourism, joining the Saale River.
Upa
A river flowing through the Tula region, historically tied to Russia’s early iron and weapons industry along its banks.
Ural
One of Europe’s longest rivers, traditionally marking part of the boundary between Europe and Asia as it flows to the Caspian Sea.
Ure
A Yorkshire river whose valley, Wensleydale, is named after it; it becomes the River Ouse after merging with the River Swale.
Urubamba
A sacred river of the Inca, flowing through the Sacred Valley near Machu Picchu before joining the Apurímac to form the Ucayali.
Uruguay
A major South American river forming part of the border between Argentina and Uruguay, eventually joining the Río de la Plata estuary.
Usk
A scenic Welsh river prized by fly fishers for its trout and salmon, flowing through Brecon and Newport to the Bristol Channel.
Ussuri
A river forming part of the Russia-China border, joining the Amur River and known for its role in a 1969 border conflict.
Usumacinta
The largest river in Mexico by volume, winding through rainforest past ancient Maya ruins like Yaxchilán before reaching the Gulf of Mexico.
Uvac
Known for its dramatic meanders and canyon scenery, this river is a nature reserve popular for its griffon vulture colonies.
Uzen (Great Uzen)
A river in western Kazakhstan that seasonally drains toward the Caspian lowlands, important for local irrigation and grazing lands.
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