The Little Roussel, also known as the Petit Ruau or Little Russel, is a channel running between the isle of Herm and Guernsey in the Channel Islands. The main harbours of Guernsey and Herm face into the Little Roussel. There are many small rocks in the channel, including , Castle Cornet (now joined to the mainland) and others. The Bréhon Tower (Fort Bréhon) is accessible only by boat and sits on Bréhon, an island in the Little Roussel about 1.5 km northeast of St Peter Port, Guernsey, between the port and Herm. The Herm ferry, from St Peter Port Harbour runs across the Little Roussel.