The river begins its race for the flatlands on the Continental Divide's backbone in Rocky Mountain National Park. During the course of its rush to join the South Platte River near Greeley, it provides more than 60 miles of public fishing. There are good populations of brown and native trout, as well as some mountain whitefish. Three sections on the river are restricted to fly and lure fishing, and on these sections the bag and possession limit is two fish, 16 inches or longer.
Part of this river has been set aside by the Colorado Division of Wildlife as Wild Trout Water.