Seyler Lane, Lewis Lane and the 2014 ruling
Three Madison County roads cross the lower Ruby on county bridges: Duncan District Road, Lewis Lane and Seyler Lane. In May 2004 the Public Lands Access Association sued, saying the adjoining owners had run fences along each road right up to the ends of the bridges so nobody could get down to the water. James Kennedy owned the land along both Seyler Lane and Lewis Lane. In October 2008 the district court ruled that the Duncan District Road and Lewis Lane rights-of-way were 60 feet wide and that the public could use that whole width to reach the river. Seyler Lane went to trial because its right-of-way had been established by prescriptive use.
The Montana Supreme Court decided the case on January 15, 2014 (Public Lands Access Association v. Madison County, 2014 MT 10). It held that the areas reasonably necessary to support Seyler Bridge and let the public use it safely are part of the road right-of-way, that a public right-of-way is not limited to the use through which it was acquired, and that recreational use is a foreseeable one. It rejected Kennedy's takings claim, affirmed the Lewis Lane ruling and sent Seyler Lane back to the district court to fix a definite width. Justice McKinnon dissented in part. The practical result for you: a county bridge right-of-way on the Ruby is a legal way to the river, and once in it you stay below the ordinary high-water mark, because the Stream Access Law does not let you cross private land to reach a stream.
Ruby Dam to Alder: four access sites on the tailwater
The Ruby leaves Ruby Reservoir about 7 miles south of Alder. The state Water Conservation Board built the earthen dam in 1938; DNRC owns it and the Ruby Water Users Association has run it since, and a two-phase rehabilitation finished in 2011 and 2014. The first fishable water is at Ruby Dam FAS, 7 miles south of Alder on the Ruby Dam Road, though the spillway area and the outlet channel up to the dam are closed to fishing all year. Vigilante FAS sits a mile downstream at 6 miles south of Alder. Alder Bridge FAS and Ruby Island FAS are reached from Alder by taking the Ruby Dam Road south and turning west on Judy Lane at the schoolhouse. Alder Bridge is a leased site, so respect the posted boundaries. None of these sites has a boat ramp, and Montana Angler says the numerous small diversion dams make floating the Ruby nearly impossible and dangerous.
Montana Angler counts two public access points in the first three miles below the dam and two more in the next six, each a small plot surrounded by private ground. This is a small stream. Expect to wade the channel itself, sometimes chest deep in the summer release, to stay off the banks.
Below Alder the river gets harder to reach
Past Alder Bridge the Ruby runs down the valley by Sheridan toward the Beaverhead near Twin Bridges. The only other FWP site is Silver Springs Bridge FAS, 3 miles west of Sheridan on Silver Springs Road. Frontier Anglers calls public access from Alder to the confluence limited, and Montana Angler describes it as some of the most difficult access imaginable, which is why the county bridges matter so much. Frontier says brown trout make up almost the entire population from the dam down; the upper river above the reservoir holds rainbows, cutthroat and grayling.
Reading the tailwater gauge as a trespass gauge
On the Ruby the flow number mostly tells you how much bank you will have to give up. Montana Angler's thresholds do not name a gauge, but they describe the tailwater and fit gauge 06020600 below the reservoir: above 100 cfs, walk-and-wade anglers may struggle to stay in the river without trespassing; above 200 it is difficult; above 300 it is impossible. Hence the 50 to 200 cfs range on this page. The same outfitter says April runs around 50 cfs early and 150 late, June peaks well above 800 and rarely drops below 300 before about June 25, July releases hold between 250 and 300, and August and September run well below 200.
The USGS record agrees. Below the dam the long-term means are 46 to 55 cfs from December through March, 419 in May, 547 in June, about 340 in July and August and 240 in September. Above the reservoir the winter mean is about 100 cfs, so the dam is holding back roughly half the winter inflow and paying it out for irrigation in summer. The tailwater fell from 262 to 151 cfs in the two weeks to September 24, 2026 as the release was cut back.
The Alder Bridge line in the regulations
The 2026 FWP regulations split the river at Alder Bridge (Ruby Island FAS). From Ruby Dam to Alder Bridge the season is April 1 through September 30 and brown trout are catch-and-release. Below Alder Bridge to the mouth there is no season exception, so the Central District's open-all-year rule applies, and you may keep 1 brown trout a day, under 18 inches. Rainbows are catch-and-release everywhere below the dam. Above the reservoir, the river from the Sweetwater Creek confluence down is open from the third Saturday in May through November 30, and all of a combined trout limit there may be cutthroat. Montana Angler states that the whole river closes December 1 to April 1; that does not match the 2026 regulation text, which closes only the dam-to-Alder reach, from October 1. FWP had no hoot-owl listing on the Ruby as of September 24, 2026; 2026 hoot-owl restrictions on the Ruby were lifted August 31.
February midges, summer PMDs and fall browns
The dam steadies the flow and the bugs respond. Montana Angler's Ruby chart has midges hatching year-round with the best dry fly action in late January through March, sizes 18 to 22; Frontier Anglers fishes Zebra Midges, Psycho Mays and olive Spanish Bullets under a small attractor near the dam in the mid-afternoon. Blue-winged olives come late March through mid-May and again mid-September into October. Caddis run late April through August with a Mother's Day push. PMDs, mostly size 16, hatch mid-June through July, and Yellow Sallies are thick from Ruby Dam down to Silver Springs Bridge from early June into July. Tricos show at sunrise in late July and August, and the hay fields along the lower river feed a hopper, ant and beetle game from late July. Montana Angler watches for the first major cold front, usually September 15 to 20, to start the pre-spawn browns chasing yellow and brown articulated streamers.