The Gallatin River is a major river located in southwestern Montana, USA. It flows for approximately 120 miles, starting in the Gallatin National Forest and merging with the Missouri River near Three Forks. The river is known for its clear waters and stunning scenery, making it a popular destination for outdoor activities such as fishing, rafting, and hiking. The river is named after Albert Gallatin, a prominent American politician and Secretary of the Treasury in the early 19th century. The Gallatin Valley, through which the river flows, is also renowned for its agricultural land and picturesque landscapes, attracting both residents and tourists alike.