South Fork of the Boise River
The South Fork of the Boise, below Anderson Ranch Dam and about 1½ hours from Boise, is Southern Idaho's premier blue-ribbon fishery for wild rainbow trout. The "SFB" is an exceptional tailwater fishery with many fish in the 12-16" range, good numbers of fish to 20", and enough reports every season of fish 25" and bigger to excite even experienced anglers.

Mid-summer usually bring lower flows (~ 600 cfs), excellent wade fishing, and the South Fork's unique midday Pink Albert hatch, followed by evening flav and caddis hatches. Late-summer and fall fishing finds the river at 300 cfs where it stays until spring. Early fall fishing focuses on hoppers, ants, beetles, and large crane flies, while cooler fall weather reduces fishing pressure on the river and brings out the Blue-wing olive hatches on cloudy days. Trout season closes at the end of November. Winter fishing regulations focus on whitefish with catch-and-release fishing for trout using midges and winter stonefly nymphs. The river closes to all fishing at the end of March to protect the wild trout during their spawning season.

The trout season on the South Fork opens Memorial Day and usually starts fishing well by mid-June with the start of the salmonfly, Golden stonefly, and early-season Caddis hatches. Early summer flows usually range from 1600 to 3000 cfs, a good range for floating in drift boats and rafts, but a difficult range for wading. Flows typically remain high until mid- to late-summer depending upon snow pack and downstream irrigation needs. Historically, September begins the wading season after the river has dropped below 1000 cfs, the preferred range being around 600 cfs. Winter flows are usually around 300 cfs.

The Upper South Fork of the Boise River, above the dam, is a freestone stream that can hold its own at certain times of the year. Like the middle fork and the north fork, it can be a great place to go throw attractor patterns early in the season. It has many of the same hatches and also holds rainbows, whitefish, and bull trout. Kokanee also run up out of the reservoir in the fall. It has two smaller tributaries, Little and Big Smoky Creeks, which can also offer good early season fishing, but they also get increasingly challenging as the flows decrease into late summer and early fall.


For current stream flow information, CLICK HERE.