Gallatin River
![](/Images/godic/202501/14/Gallatinriverwinter3310.jpg")
![](/Images/godic/202501/14/Mt-rivers3310.gif")
![Lower Gallatin River near Manhattan, Montana](/Images/godic/202501/14/LowerGallatinRiverNearManhattan3310.jpg")
![Gallatin River in full spring runoff flood near I-90 June 2008](/Images/godic/202501/14/GallatinRiverFloodNearI-903310.jpg")
The Gallatin River is a tributary of the Missouri River, approximately 120 mi (193 km long), in the U.S. states of Wyoming and Montana. It is one of three rivers, along with the Jefferson and Madison, that converge near Three Forks, Montana, to form the Missouri.