The river drains a largely agricultural area from Llandegfan to Llansadwrn and beyond, with feeder tributaries extending up towards Pentraeth forest.

More notable are the remains and ruins of a number of water mills, especially in the lower section before the river enters the strait.

It is a designated SSSI as a representative example of the Brachypodium sylvaticum, Oak / Ash (slender falsebrome oak/ash) group of broadleaved woodlands.

At the mouth of the river there is a small group of houses called Cwm Cadnant below which is a modern bridge carrying the main road to Beaumaris.

Before the construction of the Menai Suspension Bridge, this was an important landing stage for boats carrying milled corn to the mainland.