What the Paria is
The Paria rises below the Pink Cliffs near Tropic, runs about 95 miles south-southeast across Kane County and Grand Staircase-Escalante National Monument, cuts through the Vermilion Cliffs in Paria Canyon and joins the Colorado at Lees Ferry, Arizona. Its name comes from a Paiute word for muddy water, and that is the river: a warm, silty wash averaging about 28 cfs at the mouth, dry in stretches in late spring, and capable of 16,000 cfs in a flash flood. It holds no trout and Utah does not manage it as a fishery.
White House trailhead and the canyon
The White House trailhead, two miles south of US 89 near the Paria Contact Station, is the start of the 38 mile Paria Canyon hike to Lees Ferry and the upstream approach to the Buckskin Gulch confluence. Overnight trips need a BLM permit reserved online, with 20 people a day allowed across the four trailheads, and day hikes use the self-pay stations. The canyon has no exits for miles, so flash floods from July through September are the real hazard; check the forecast at the BLM office in Kanab.
Paria townsite and Cannonville
The old Paria townsite, a ghost town and movie set off US 89 east of Kanab, gives road access to the river valley above the canyon, and the upper river passes Cannonville and Kodachrome Basin near Bryce Canyon. These are places to see the country, not to fish.
Season and regulations
This page keeps a flow reading because the gauge decides whether the canyon is walkable. The USGS gauge at the Highway 89 bridge near the White House trailhead shows typical base flows between 1 and 35 cfs, often a bare trickle or dry in May and June, and anything rising fast means a flood is on the way; the 1 to 30 cfs band here is a base-flow window for hikers, not a fishing range.
There is no trout season or trout regulation on the Paria because there are no trout. Anyone who wants Utah trout nearby should look to the Sevier drainage or the Boulder Mountain lakes. A BLM permit is required for overnight travel in Paria Canyon-Vermilion Cliffs Wilderness; check the BLM Kanab field office for current permit rules and flood conditions.