Fly Fishing Mammoth Creek - Hatch Valley

Mammoth Creek through Hatch Valley is one of Southern Utah's premier wild brown trout streams, flowing 23 miles from its headwaters on Mammoth Mountain at 9,680 feet down to 6,900 feet near the town of Hatch. This intimate freestone creek is naturally abundant with wild brown trout and supports stocked rainbow trout, occasional brook trout, cutthroat, and mountain whitefish. The nine-mile regulated section between the Canal Diversion and Hatch Meadow consistently holds browns up to 19 inches, making it a destination for anglers willing to explore Southern Utah's quieter waters.

The creek's character varies dramatically along its length. The upper reaches tumble through timbered canyon with pocket water and plunge pools, while the Hatch Meadow section opens into classic meadow stream — slow bends, undercut banks, and grassy margins that demand a careful approach. Flows average around 50 cfs annually but swing from as low as 6 cfs in drought years to over 160 cfs in wet seasons. The prime wading window of 15-60 cfs provides outstanding conditions from July through October. Spring runoff typically muddies the creek in May and early June.

Hatch timing on Mammoth Creek follows the Southern Utah pattern — midges dominate winter through early spring (sizes 18-24, best 11am-2pm), with BWOs arriving mid-March and peaking in April and October. Caddis emerge in late May and carry through September, with explosive evening activity in June and July. Yellow Sallies appear in July. But the real magic is terrestrial season: the Hatch Meadow's open grasslands produce outstanding hopper fishing from mid-July through September, with August being peak. Ants and beetles round out the summer dry-fly menu.

Access requires some local knowledge. Most of Mammoth Creek crosses private land — anglers should obtain permission and respect posted boundaries. The regulated section from the Canal Diversion upstream through Hatch Meadow offers the best fishing. From Hatch, head south on US-89 and look for county road access points. Cedar City Regional Airport (CDC) is about 50 miles northwest. The creek sits within the Bryce Canyon Country fishing corridor alongside the upper Sevier River, Asay Creek, and Panguitch Creek, making it an excellent base for a multi-day Southern Utah fly fishing trip.