Hi,
The Boise River is perhaps the best known spot amongst fishing enthusiasts specially for trout and the one I would suggest for fly fishing.
Because the river runs through the
city of Boise, it passes through public parks such as Barber Park and Eagle Island making these spots the most convenient places to do fly fishing.
Another great spot for
fishing is the Salmon River which is a great place for fishing of Steelhead between the months of March and April.
Be aware, the Upper part of Salmon River is located in the Sawtooth National Forest, and therefore you will need a special Sawtooth National Recreation permit in order to fish these waters.
The Lower Salmon River is better for fly fishing and fishing of Steelhead if you travel between September September and November.
Travadvice360