Starting this Thursday, Oct. 15, Montana Fish, Wildlife & Parks says the bighorns near Thompson Falls are at their easiest to see. That window stays open until May 1. The interpretive signs at the pullout still describe a herd in the hundreds. The most recent published count of the Thompson Falls herd was 50 sheep. Since 2025, FWP crews have fitted 22 of them with GPS satellite collars, and the rams' collars are programmed to record a location every 30 minutes through the breeding season.
That's the herd you'll be watching from the bench this winter. There are fewer sheep than the signs suggest, and more people are tracking where each one goes.
The pullout east of mile marker 59
The Bighorn Viewing Area sits on the north side of Highway 200, just east of mile marker 59. Madison Heiss described it in a Sanders County Ledger column this June. She noted the benches facing the field and the mountains, and about ten signs covering sheep behavior, diet, plant life and geology.
FWP manages the ground as the Bighorn Viewing Site Wildlife Management Area. The agency calls it a small WMA that protects important lambing and spring habitat. Access is walk-in only, though FWP notes the sheep are usually seen from the highway.
Timing is what matters this week. FWP's conservation strategy describes the herd making a short seasonal migration. The sheep move up into higher timbered country between late April and mid-May, then come back down to their lower winter habitat in October. For most of the summer, the hillsides you drive past are largely empty of sheep. Right about now, they start filling back in.
What the signs say, and what the counts say
The Ledger column passed along one of the signs' facts. Each herd numbers about 300 sheep, Montana has only 30 herds, and the Thompson Falls herd is one of the largest. That was close to true once. Here is how the herd's documented numbers have moved:
- 1959. FWP reintroduced bighorns here with 13 sheep from the Sun River herd and six from Wild Horse Island.
- 1984. The spring survey observed 432 sheep, according to FWP's 2010 bighorn sheep conservation strategy. A 2022 Valley Press/Mineral Independent report put that same peak at 425.
- 2008. FWP estimated the herd at 300 to 325 animals. The agency cautioned that dense forest cover made a full count impossible.
- 2021. The count was 50, according to the Valley Press/Mineral Independent, which added that the decline was "not linked to any one cause."
The signs' "around 300" matches the 2008 estimate. The 2021 figure is the latest herd-wide count in the published record, and no newer total has been released since. That same 2022 article cited an ideal herd size of about 125 sheep for protection and genetic diversity. It also noted that many Montana herds do well with fewer.
The Thompson Falls herd is one of four along Highway 200 between the National Bison Range and the Idaho line. The others are the St. Regis Cut-Off, Berray Mountain and Perma-Paradise herds. In the same 2021 counts, Perma-Paradise stood at 248, Berray Mountain at 31 and St. Regis Cut-Off at 21. The herd closest to town went from the largest in the 1980s to the smaller end of its neighbors.
Twenty-two collars, and a rut on the record
Here's what makes this particular fall different. FWP's adaptive management annual report for bighorn sheep and mountain goats, dated Aug. 31, 2026, has a section on the Thompson Falls population. Crews have captured 22 sheep by ground darting. That was 15 ewes and five rams in fiscal year 2025, then two more ewes in fiscal year 2026.
Each sheep in the project wears a Lotek Iridium-GPS satellite collar. Thompson Falls is also part of a separate study of how wild sheep interact with domestic animals. That puts its rams' collars on a special schedule. They log a position every two hours from January through September, then every 30 minutes from October through December "to capture finer scale movement during the breeding season." Every collar in this herd also carries virtual fences drawn around known domestic sheep and goat grazing areas.
Under that schedule, the higher frequency starts this month. Any collared ram still transmitting is set to log its position every half hour while it spars on the slopes above the highway. The report even includes a photo of two Thompson Falls rams squaring off, with a note that the ram on the left had been captured and collared.
"None of the captured sheep tested positive for M. ovi at the time of capture."
That refers to Mycoplasma ovipneumoniae. The same report says pneumonia outbreaks and die-offs in bighorns are often set off by this bacterium. Samples came back negative from all 20 sheep tested in fiscal 2025 and both tested in fiscal 2026. Ten of the 14 ewes that gave blood samples were pregnant when captured. These are results from the captured sheep only. They aren't a verdict on every animal on the mountain. The herd section also reports that three of the five ram collars have failed, and it lists those rams' fates as unknown. A failed collar stops sending locations, so the 22 is a running total of sheep collared, not a count of collars transmitting today.
Why the sheep end up so close to the road
The collars also confirm a risk anyone who drives this stretch already knows about. Two collared ewes have died since the study began. One death, on Sept. 9, 2025, was attributed to natural causes. The other, on June 21, 2025, was a vehicle collision.
The same geography that makes these sheep easy to watch puts them on the highway. FWP describes the herd's range as about 140 square miles along the Clark Fork between Thompson Falls and Plains. Its core is roughly 90 square miles running from Weeksville Creek to the Thompson River. About 90 percent of that habitat is Lolo National Forest land. FWP also manages Mount Silcox and Roundhorn as public-access areas within the range.
Historically, the sheep showed up on or beside Highway 200 from November through May. In winter they were drawn by the salt in road deicer, and in spring by the first green growth along the shoulders. The Valley Press/Mineral Independent counted roughly 450 sheep killed by vehicles on Highway 200 between 1985 and 2021. The paper called that figure a minimum.
Much of what you pass on your drive into town exists because of this herd:
- Flashing lights and signs, plus 55 mph speed limits that came to parts of the highway in 2013.
- Fencing between mile markers 58 and 59, added in 2019, on the same stretch as the viewing area.
- Electric roadway mats near the Thompson River that give sheep a shock when they step on them.
- Fenced sections west of Thompson Falls and east of Plains that keep bighorns off the highway and railroad tracks, according to FWP's 2024 migration action plan update. That update still calls the corridor an important source of bighorn mortality.
The 2022 article credited these measures with reducing collisions. Once salt goes down on the highway this winter, those flashing signs between Weeksville Creek and the Thompson River are telling you something real.
The tag almost nobody draws
This herd is also FWP Hunting District 121, one of three bighorn districts in Sanders County open to hunting. The 2022 Valley Press/Mineral Independent piece reported that the county's four districts together issued only 11 ram permits and two ewe permits a year. A little over 2,600 hunters applied for those 11 ram tags.
Those odds explain why a big ram on the hillside east of town gets so much attention. FWP keeps a close eye on the herd for the same reason. FWP has tracked the Sanders County herds since 1980 and flies observation surveys each spring to check their numbers and condition.
Making the most of the bench this winter
The signs at the pullout cover biology, management and valley history. FWP considers them one of the site's main features. They're worth reading with the newer numbers in mind. The 300-sheep figure is a snapshot from around 2008. The animals in front of you now belong to a smaller herd that wildlife biologists are following through the breeding season in finer detail than ever before. If you spot a collar on a ewe grazing near the fence line, she's one of the ewes FWP crews have collared since 2025.
The Ledger column suggested packing a lunch, bringing a book, and staying for a while. The viewing window opens Oct. 15, and the breeding season runs through December.
I've spent a lot of years driving Highway 200 between Plains and Thompson Falls, and that pullout east of mile marker 59 is still one of my favorite stops on the river corridor. If you're thinking about land along the Clark Fork and want to know what living near this herd and its range looks like through the seasons, Deborah Warren is happy to talk it through. Contact Deb for a local market consult.
