It is the longest tributary of the Yeşil River.

It is the longest tributary of the Ledava.

It is the longest tributary of the Weißeritz.

They lived around the upper Main, which is the longest tributary of the Rhine.

At 176.7 km in length, it is the longest tributary of Tonegawa.

Most rivers have numerous tributaries and change names often; it is customary to regard the longest tributary as its source.

Stretching for 129 km, it is the longest tributary of the Šventoji River.

The Tawa is the Narmada's longest tributary, at 172 km.

It is a 65 km long tributary of the river Oust.

The Xun is also a section of the Pearl's longest tributary.