The Smith River is an excellent river for both brown trout and rainbow trout. While the Smith River does not hold significant amounts of large fish, the river does hold lots of trout between 13-16 inches. What the Smith River lacks in very large trout, however, it makes up in relative ease of catching trout. Unlike many other popular Montana rivers, fly fishing the Smith River does not require precise fly imitations, light leaders and perfect presentation - although all of the above certainly will increase both your catch rate and the size of fish caught.
This section of the Smith River has both large populations of brown trout and rainbow trout, with brown trout generally out-numbering the rainbow populations. For the fly angler willing to brave the elements, April can provide for excellent fishing. Strong stonefly hatches occur in the Smith River generally beginning in mid to late April and last through the middle of May. Fly patterns for this hatch include the standard Elk Hair Caddis for dry fly fishing and the Prince Nymph for sub-surface fishing, in sizes 10-14.
The Smith River has a strong salmonfly hatch that occurs beginning in mid-May and can last through June, depending on weather and river conditions. Popular fly imitations include the Stimulator, Kaufmann's Stone and Bitch Creek Nymph, in sizes 4-8. Beginning in the middle of June and lasting throughout the summer, the Smith River is an excellent river for dry fly fishing for rainbow trout using standard caddis fly imitations, such as the Elk Hair Caddis and X-Caddis, in sizes 14-18. Generally, the caddisfly hatches occur in the early morning and again later in the evening. While top water fishing using standard dry flies may not catch the largest trout in the river, it is effective and can land a fair number of decent sized trout.
For anglers in search of brown trout, the numerous deep pools in the Smith River provide wonderful places to catch the larger fish. Use large streamers or Wooly Buggers, working them down in the deep pools. Also work them around any undercut banks and around obstructions in the river. This is probably the most effective way to catch the larger trout during the summer months.