It is named for a now - extinct geyser ( Soda Butte ) near its mouth .
Soda Butte Creek is an approximately 20 miles ( 32 km ) long major tributary of the Lamar River in Yellowstone National Park .
Soda Butte Creek is named for a now - extinct Soda Butte Creek ( Soda Butte Creek   ) near Soda Butte Creek 's mouth .
Soda Butte Creek is an approximately 20 miles ( 32 km ) long major tributary of the Lamar River in Yellowstone National Park .