The Tamar's source is less than from the north Cornish coast, but it flows southward and its course runs across the peninsula to the south coast. The total length of the river is . At its mouth, the Tamar flows into the Hamoaze before entering Plymouth Sound, a bay of the English Channel. Tributaries of the river include the rivers Inny, Ottery, Kensey and Lynher (or "St Germans River") on the Cornish side, and the Deer and Tavy on the Devon side.