The Big Wood River is Sun Valley's secret weapon — a 10-month-a-year trout fishery flowing through the heart of Idaho's most glamorous resort community that most visitors walk past without realizing it holds world-class brown and rainbow trout within walking distance of Ketchum's finest restaurants. While the nearby Snake River drainages attract most of the fly fishing attention, the Big Wood quietly produces some of the best urban trout fishing in the Mountain West, with fish averaging 12 to 18 inches in an easily accessible stream corridor that threads through Ketchum, Hailey, and Bellevue.
The Big Wood originates in the high peaks of the Sawtooth and Boulder-White Cloud mountains and flows south through the Wood River Valley before eventually losing itself in the Snake River Plain. The upper river from Ketchum to Bellevue — approximately 25 miles — is the prime trout water, with the regulated sections between Ketchum and Bellevue receiving the most attention from local guides and visiting anglers. Brown trout dominate the lower sections, while rainbow trout and mountain whitefish fill the upper reaches.
The hatch chart on the Big Wood is exceptional — a near year-round procession of insects that provides some form of surface activity in every month except the coldest weeks of deep winter. Green drakes in June are the headliner, producing some of the most spectacular surface feeding of the season as large fish push into the riffles and run banks to eat the large mayflies. PMDs follow through July and August, overlapping with summer caddis hatches that produce prolific evening activity. Late summer brings hopper season and fall delivers BWOs and red quills. Midge fishing remains productive even in winter.
The Big Wood is a relatively small river — rarely more than 40 feet wide in prime sections — which makes accurate casting and stealthy approaches essential. Brown trout in the Ketchum reach are highly educated, having seen every pattern in the book from legions of resort-visiting fly anglers. These fish require light tippet (5X minimum, 6X on glassy runs), accurate presentation, and realistic fly selection. The reward is hook-ups with wild, large trout in a setting that combines mountain scenery with the amenities of a world-class resort town.
Bellevue and Hailey-area shops like Silver Creek Outfitters and The Ketchum Outfitters can put you on the best water and match the day's hatch precisely. The Wood River Valley's extensive trail and bike path system doubles as fishing access, making it possible to cover miles of river on foot.
