Fly Fishing Middle Fork Powder River - Barnum

Fly fishing the Middle Fork of the Powder River near Barnum is one of Wyoming's best-kept secrets — a Blue Ribbon freestone stream tucked into the southern Bighorn Mountains that produces surprisingly large trout for its diminutive size. The Middle Fork drains roughly 45 square miles of mountain terrain before joining the main Powder River system, flowing through a mix of open sagebrush parks and timbered canyon stretches south of the town of Barnum in Johnson County. Despite its small water profile, this creek consistently holds brown trout averaging 14 to 16 inches with fish to 20 inches lurking in the deeper pools and undercut banks — a testament to the cold, spring-fed tributaries and healthy insect life that sustain the fishery.

The character of the Middle Fork shifts dramatically along its length. Upper reaches tumble through narrow timbered canyons with plunge pools and pocket water where brook trout and rainbow trout share space with browns. As the stream opens into wider meadow sections near Barnum, the gradient mellows and the river takes on classic small-freestone character: riffle-run-pool sequences, gravel bars, and willow-lined banks that create overhead cover for wary fish. Flows are modest — USGS gage 06309200 typically records base flows between 3 and 15 cfs in late summer, with spring runoff pushing to 80 cfs during peak snowmelt. The small flows mean precise presentations are critical, and long leaders with light tippet (5X-6X) are standard even on a freestone stream.

The hatch calendar follows a typical central Wyoming freestone pattern but compressed into a shorter mountain season. BWOs are the first significant hatch, appearing in April and May as snowmelt begins. The Mother's Day Caddis emergence in May transitions into prolific spotted sedge hatches that carry through summer evenings. PMDs hatch from late June through August, providing the best dry-fly fishing of the year on calm mornings and overcast afternoons. Golden Stoneflies emerge in July along the rockier canyon stretches, and Yellow Sallies overlap through midsummer. Terrestrial fishing — hoppers, ants, and beetles along the meadow banks — is outstanding from mid-July through September. The brown trout here are opportunistic feeders, and a well-placed hopper pattern tight to an undercut bank can draw explosive strikes from fish that seem impossibly large for the water they inhabit.

Access to the Middle Fork Powder River requires some navigation. The stream crosses a mix of BLM land, Wyoming state land, and private ranch property. The most reliable public access is through BLM parcels south of Barnum along county roads, and Wyoming's stream access law allows wading within the ordinary high-water mark on navigable waters. Respectful communication with landowners can sometimes open additional access. Wyoming Game and Fish Department manages the fishery under standard Region 2 regulations — no special gear restrictions apply, though catch-and-release is strongly encouraged to maintain the quality of the fishery.

Sheridan County Airport (SHR) is the nearest commercial service, approximately 90 minutes north. The drive from Sheridan passes through the heart of the Bighorn Mountain country, and anglers can combine a trip to the Middle Fork with nearby waters including the Tongue River headwaters and the main Powder River system. For those willing to explore beyond the famous destination rivers of western Wyoming, the Middle Fork Powder River near Barnum delivers Blue Ribbon quality trout fishing in a setting where you may not see another angler all day.