Highway 14 from Kooskia to the Red River
Everything on the South Fork hangs off one road. The river forms at 3,901 feet where the American and Red rivers meet in the Nez Perce National Forest, then runs west through a canyon that Idaho Highway 14 follows, picking up the Crooked River from the south and Newsome Creek from the north before Golden, where Tenmile Creek comes in. Below Golden it gathers Johns Creek, Meadow Creek and Mill Creek, and the gorge deepens to about 2,000 feet as the river swings north near Grangeville. From there it runs north past Harpster and Stites and meets the Middle Fork at Kooskia, at 1,224 feet, to form the Clearwater.
Idaho Fish and Game's planner puts the South Fork at 62.9 miles, all in Idaho County, and lists toilets, campgrounds and ADA access along it but no boat ramp. Treat it as road-and-wade water: with Highway 14 following the canyon, most days start from a pull-off and a walk down the bank, and there is no ramp to plan a float around.
The Harpster dam came out in 1963
The Grangeville Dam, also called the Harpster Dam, stood on the South Fork 5 miles east of Grangeville: an arched concrete wall 56 feet tall and 440 feet long, built by the Grangeville Power and Light Company in 1910 and 1911. Its wooden fish ladder collapsed in 1949. Washington Water Power, which owned it by then, took it down for fish passage on August 19, 1963, on the third detonation of the day, and it held the record as the largest dam ever removed for decades afterward. The South Fork and its headwater streams have run free ever since. In 1999 Avista, the renamed utility, settled with the Nez Perce Tribe for $39 million over fish losses caused by this dam and the Lewiston Dam.
IDFG still puts a lot of hatchery steelhead into the reopened river. Its stocking record shows 251,033 steelhead released on March 25, 2026 and 342,875 on March 23, and in 2020 the Clearwater River Company in Orofino passed along a call from IDFG's Clearwater regional fisheries manager for anglers to help collect local broodstock on the South Fork.
Fall 2026 steelhead dates, and the barbless hook rule
Idaho's steelhead water on this river runs from the mouth upstream to the confluence of the American and Red rivers. For fall 2026, IDFG's season page shows harvest open September 10 through October 14, seven days a week, with a daily limit of 2 steelhead, only 1 of them 28 inches or longer, 6 in possession with no more than 3 at that length, and 20 for the fall season. The 2025 to 2027 brochure then has October 15 to November 9 as catch-and-release and November 10 to December 31 open again at 2 a day. The spring season runs January 1 to April 30 at 3 a day. Only fish with a clipped adipose fin, shown by a healed scar, may be kept, and a steelhead permit is needed. IDFG says fall fishing is best on the lower Clearwater, and anglers find fish up the South Fork as they migrate.
On the South Fork only single-pointed barbless hooks may be used when fishing for steelhead or salmon. Coho are open September 1 to December 31, 2026 from the mouth to the Red River, 2 adults a day. Spring and summer Chinook seasons are set separately by the Fish and Game Commission, and salmon fishing is closed unless a season is opened for this water.
Two trout, no cutthroat, and every bull trout back
For trout the South Fork follows the Clearwater Region's general rules with one change. The region is open all year; the rivers-and-streams trout limit is 2, all species combined, but on the South Fork cutthroat are catch-and-release only, so in practice the 2 you keep are rainbows. Bull trout must be released everywhere in the region. Brook trout are separate, with a limit of 25, and whitefish are 25. Remember that in the Clearwater drainage below Dworshak Dam, any rainbow longer than 20 inches is legally a steelhead, and steelhead rules apply to it.
IDFG's 2022 survey list for the river includes westslope cutthroat, rainbow trout, brook trout, mountain whitefish, Chinook salmon, northern pikeminnow and smallmouth bass; steelhead were recorded in 2018 and bull trout in 2013. Smallmouth have no bag or size limit in Clearwater Region rivers.
A lower-end gauge that sees nearly the whole basin
USGS 13338500 at Stites sits near the bottom of the river at Stites, the last town the river passes before Kooskia, and drains 1,168 square miles of a basin of about 1,175. It tells you what the whole South Fork is doing, but the canyon above Golden runs far smaller than the Stites number. The long-term means since 1911 peak at 3,197 cfs in May and 2,347 in June, then fall to 259 in August, 219 in September and 261 in October.
No shop publishes a wading range for Stites. The 136 to 297 cfs band on this page is the gauge's own record: the 25th to 75th percentile daily flows between September 1 and October 15. On September 24, 2026 Stites read 166 cfs, inside that band. A sharp jump in fall usually means rain, and it will color the lower river first.
Bugs borrowed from the Selway and Kelly Creek
Nobody publishes a hatch chart for the South Fork, so the calendar here leans on RiverReports' tables for two neighboring Clearwater drainages: the Selway, which starts with skwalas in May, then salmonflies and golden stones in mid-June, hoppers in July, PMDs and caddis in July and August, and October caddis in September and October; and Kelly Creek, which adds yellow sallies in July and August, tricos in August and September, and blue-winged olives in September and October. For steelhead, the same writers' Clearwater box starts with Green Butt Skunks and Purple Perils in sizes 4 to 6.