Clark's clear stream runs two ways
William Clark named the Judith on May 29, 1805, for Julia Hancock, the cousin he later married, because he thought it particularly clear and pretty. It still starts that way. The forks rise in the Little Belt Mountains of the Lewis and Clark National Forest, cold enough for brook trout and cutthroat, and the river flows northeast past Utica and Hobson, picking up Dry Wolf Creek in northern Fergus County. By the time it meets the Missouri in the White Cliffs country about 18 miles northwest of Winifred, it is a warm plains river where FWP's nets turn up channel catfish and sauger far more often than trout.
Decide which river you are driving to before you leave. Trout anglers want the foothill water around Utica and the forks above it. Anglers after catfish, sauger and burbot want the lower river through the Missouri Breaks. The regulations split at the same place the fish do.
Utica, Sapphire Village and the forks
Utica is a crossroads of 23 people on Montana Route 239, about 40 miles from Lewistown, where Yogo sapphires turned up in the 1890s and a young Charlie Russell worked cattle. From U.S. 87 at Windham, seven miles east of Stanford, Route 239 runs 11 miles south to town. From there the main gravel road follows the north side of the Judith for 9 miles to Sapphire Village; the first right past the village leads 1.5 miles to the headquarters of FWP's Judith River Wildlife Management Area, 9,397 acres that open at noon May 15 and closes December 1, with pack-in, pack-out primitive camping and no commercial use.
FWP lists no fishing access site anywhere on the Judith mainstem, so the national forest and the WMA roads are where a walk-in angler starts. The Judith River Ranger Station on the Middle Fork, listed on the National Register in 1992, is now a campground and a rental cabin. Above it the Middle and Lost forks cut limestone canyons through the Middle Fork-Judith Wilderness Study Area, about 92,000 acres. Below the Big Spring Creek confluence the Judith is Class I water under the stream access law.
What the survey nets turned up, top to bottom
FWP's electrofishing records give a truer picture than any shop blurb. On the Middle Fork in 2023, crews at the Lost Fork, Guard Station and private-land sections found mostly brook trout and small rainbows, few of them over 300 millimeters, plus the odd westslope cutthroat. The mainstem below Utica is brown trout water: the 2020 section from Antelope Creek Road to Ackley Lake Road produced 116 browns averaging 320 millimeters, about 12.6 inches, with the largest at 480, along with 17 whitefish and 5 westslope cutthroat. A 2023 pass at the Wertheimer section handled 68 browns averaging 305 millimeters.
Downstream the list changes completely. Hoop nets and jet-boat electrofishing near the PN Bridge and Anderson Bridge since 2015 have caught channel catfish up to 900 millimeters, blue suckers over 800, burbot, sauger, goldeye and shorthead redhorse, with smallmouth bass in a 2017 Roe Ranch sample. A few big rainbows show up too, including a 560 millimeter fish in the 2024 PN hoop nets.
Highway 81 is the district line
Montana's Central and Eastern fishing districts meet on State Route 81, which crosses the Judith north of Hobson, and the 2026 regulations follow that line. Upstream of Highway 81 the river gets Central District standard rules: open all year; combined trout 3 daily and in possession, only 1 over 18 inches and only 1 cutthroat; grayling released immediately; brook trout 20 daily. Roadways used as the boundary count as Central District.
From Highway 81 downstream to the mouth, the Judith is Eastern District water and is listed as an exception: sauger and walleye 5 daily with only 2 sauger, and a possession limit of 10 with only 4 sauger. Otherwise the Eastern standard applies, so trout are 5 daily in rivers, channel catfish 10 daily and 20 in possession, and burbot 5 daily. The mouth itself is on the Upper Missouri National Wild and Scenic River, where BLM's Judith Landing campground at the PN Bridge opens May 15 through October 15 with eight first-come sites for trailers up to 40 feet.
A creek-sized gauge above Carr Creek, and a borrowed bug list
For the trout water, read USGS 06110020, Judith River above Carr Creek near Utica. The gauge near Winifred measures the prairie river and says little about wading conditions in the foothills. The Utica record only runs from 2014 to 2025, and it shows how small this river is: monthly means of 6 to 8 cfs in winter, 17 in April, 215 in May and 217 in June, then 80 in July, 29 in August, 19 in September and 17 in October. No shop publishes a wading range for this gauge, so the 17 to 80 cfs range here is simply the July-to-October span of those means. FWP holds a 25 cfs instream reservation from the forks to Big Spring Creek, and late-summer means fall below it, which is worth thinking about before you land a fish on a hot afternoon.
We found no shop hatch chart for the Judith, and no Lewistown or Great Falls shop page describing its bugs. The table below borrows timing from Grizzly Hackle's western Montana chart and should be treated as a general guide for a small east-slope freestone: blue-winged olives in spring and fall, caddis through summer, pale morning duns and golden stones in early summer, hoppers from August into September.