Weasel Creek—K: 9—1895—U. S. G. S.—Characteristic.
Willow Creek—H: 14—1885—U. S. G. S.—Characteristic.
Winter Creek—E: 6—1885—U. S. G. S.—Characteristic.
Witch Creek—O: 8—1878—U. S. G. S.—Probably from the prevalence of hot springs phenomena along its entire course.
Wolverine Creek—R: 8—1885—U. S. G. S.—Characteristic.
Yellowstone River (8,100 and 5,360)—U: 16 (enters map); A: 5 (leaves map).—See [Part I, Chapter I].