Which 32 km meltwater stream is the longest river in Antarctica?

Which 32 km meltwater stream is the longest river in Antarctica? The answer is the Onyx River.

The Onyx is a seasonal meltwater stream in Antarctica’s Wright Valley. It flows west from Wright Lower Glacier and Lake Brownworth to Lake Vanda, reaching its greatest flow during the brief Antarctic summer. Although called a river, it is endorheic: its water does not reach the ocean because the valley is blocked by glacier and terrain.

The river’s 32 km course makes it Antarctica’s longest, but it is not a permanently flowing waterway. Its discharge depends on summer melting, and it can disappear or shrink dramatically during the colder months. Several meteorological and research stations operate along or near its course.

A common mix-up is confusing length with size. The Onyx is the longest Antarctic river by channel length, not the continent’s largest by flow or drainage basin. Antarctica’s ice-covered environment also means that ordinary comparisons with temperate rivers require care.