The River Tamar is a significant river in southwest England, forming part of the border between Devon and Cornwall. It stretches approximately 61 miles (98 kilometers) from its source near Tavistock to its estuary at Plymouth Sound. The river is known for its scenic beauty and rich biodiversity, supporting various wildlife habitats. The River Tamar has historical importance, serving as a trade route and a boundary between the two counties. It is also popular for recreational activities such as boating, fishing, and walking along its banks. The river's estuary is a designated Area of Outstanding Natural Beauty, attracting visitors year-round.