"It [the Rush] had everything you could want on an occasion of that sort—rumbling waterfalls, silver cascades, deep, amber-coloured pools, mossy rocks, and deep moss on the banks in which you could sink over your ankles."
―Chapter 10[src]

The River Rush was a small, southern tributary of the Great river during the Golden Age of Narnia. It joined the Great River at the Fords of Beruna.

Appearance in "Prince Caspian"

By the time of the Narnian Revolution, the Rush had become a gorge. The four Pevensies and the Dwarf Trumpkin traversed this gorge on their journey to reach Caspian X at Aslan's How.

River gorge pevensies

The Pevensies & Trumpkin at the gorge of the River Rush, in the 2008 movie.