Grannis is the only state site
The Shields runs 65 miles, by FWP's measure, from Fawn Creek on the west slope of the Crazy Mountains south through the Shields Valley past Wilsall to the Yellowstone near Livingston. FWP lists exactly one fishing access site on it: Grannis FAS, under an acre at river mile 3, just east of Highway 89 and 4 miles north of Interstate 90, with camping but no boat facilities. Mayor's Landing, Sheep Mountain off the Convict Grade Road, and the Highway 89 Bridge site show up in searches for Shields access, but FWP lists all three on the Yellowstone. Everywhere else you are reaching the water at county road bridges and staying inside the ordinary high-water mark, which the Stream Access Law allows; it does not let you cross private land to get there.
FWP's angler counts show how the valley gets used. On the reach from river mile 20.85 to 32.8 anglers logged 563 days in 2017, 6,605 in 2020 and 1,841 in 2021. The upper river above mile 32.8 saw 544 angler days in 2021. It is not a crowded river, and landowners along it notice who is on it.
Cutthroat in the headwaters, and why FWP poisoned a creek
FWP lists Yellowstone cutthroat trout, mountain whitefish, mottled sculpin and several suckers and dace as native to the Shields, and brook, brown and rainbow trout as introduced. The agency says cutthroat numbers in the upper watershed have declined largely because of brook trout, and that the high-elevation headwaters hold a core conservation population at the northernmost edge of the species' range. FWP and the Custer Gallatin National Forest began removing brook trout in 2022. In August 2026 crews treated Dugout Creek and other upper basin streams with rotenone after collecting the cutthroat to put back, and the Forest Service closed the upper Shields drainage on National Forest land from August 10 through 18. FWP's stocking records show the last cutthroat plant in the river in 1970.
Lower down, the valley is ranch country; FWP notes extensive logging in the headwaters and grazing and farming below.
Kill every smallmouth, count your cutthroat
The 2026 FWP regulations have one Shields River rule, and it is about bass. On the entire river, every smallmouth bass caught must be killed and kept, reported to FWP within 24 hours at 406-577-7900, and the whole fish taken to an FWP office within 10 days; frozen is fine and FWP returns the fillets if you ask. Everything else follows the Central District standard limits: the season is open all year, 3 trout daily and in possession with only 1 over 18 inches and only 1 cutthroat, 20 brook trout, and 20 whitefish daily. With a native cutthroat population under restoration upstream, releasing every cutthroat is the sensible choice.
Hoot-owl comes early on cutthroat water
FWP usually restricts fishing when the daily maximum water temperature reaches 73 degrees for three straight days, but in cutthroat trout waters the trigger is 66. That difference matters here. In 2026 FWP put the Shields under hoot-owl hours, no fishing from 2 p.m. to midnight, from the bridge above Wilsall between Jordan Bench and Pinkerton roads down to the Yellowstone on July 22. On August 18 it lifted the upper part, from that bridge to Brackett Creek Road, and kept the restriction below; on August 31 it removed the rest. FWP's release said staff were working with irrigators to improve flows. Plan summer trips around mornings and check the FWP restrictions page first.
A May river that runs out of water
The Livingston gauge on this page sits a mile above the mouth. Its long-term means peak in May at 889 cfs, earlier than the big rivers around it, then fall to 277 in July, 106 in August and 114 in September. No shop publishes a flow range for the Shields, so the 100 to 280 cfs band here is simply that post-runoff USGS record from August back to July. Recent summers have been far below it. The August mean was 44 cfs in 2025 and 43 in 2026, and on August 12, 2026 the river read 29 cfs at Livingston. Up the valley, the gauge below the South Fork near Wilsall read 14 cfs on September 24. In summers like those the lower river is thin, warm water; fish it early in the day or leave it alone.
Borrowing the Yellowstone's bug calendar
No shop publishes a Shields hatch chart. The closest is Sweetwater Fly Shop's Yellowstone River list from Livingston, a few miles from the mouth, and on this smaller, warmer tributary it is a rough guide only. Midges, size 16 down to 24, carry November through March. Mother's Day caddis start around the third week of April. PMDs come June into early September, golden stones from late June to early August, and Yellow Sallies from mid-July well into August. Hoppers and other terrestrials run August into October, and blue-winged olives are best in September and October. On the Shields, a hopper with a small nymph dropped off it, fished early in the day, covers most of the summer.