Newcastle's River is the River Tyne, which is a river in North East England that flows from the Northumberland National Park to the North Sea. It is approximately 125 miles long and has been an important part of the region's history for centuries. The river has been used for transportation, industry, and recreation, and is a popular tourist destination. The River Tyne is also home to many species of fish and wildlife, making it an important part of the local ecosystem.