"Sitting here, looking at that wonderful overpass and thousands of antelope come through here," Gov. Mark Gordon told the Pinedale Roundup, in a story reprinted by Wyoming Public Media, on June 26. "We must protect them."
He said it at Trappers Point, the hill above the Trappers Point Overpass a few hundred yards off Cora Junction, while signing the Sublette Antelope Migration Corridor into place. His office calls it the longest antelope migration corridor in the continental United States. This is the first fall the herd has come south under that designation. The animals use the same strip of ground near Cora that they have used for thousands of years. Hunters, ranchers, highway engineers and now state policymakers have all worked around that strip.
Why the herd funnels past Cora
The Sublette pronghorn herd covers a huge area. The Wyoming Game and Fish Department says the herd spends summer in the Wyoming Range foothills, around Bondurant and in Jackson Hole. Each fall it moves south to lower winter range near Pinedale, Green River and Rock Springs. USGS mapping built from GPS collar data shows some animals summering as far north as Grand Teton National Park along the Path of the Pronghorn. Others stay in the Bondurant Valley, the Gros Ventre Mountains or the Wyoming Range. Winter range runs from Pinedale south to Rock Springs and into the western Red Desert.
The herd also mixes different habits. In that USGS dataset, 55 percent of tracked pronghorn made distinct seasonal migrations, 32 percent were nomadic and 12 percent stayed put. Tracked females averaged nearly 60 miles one way, and some traveled more than 200 miles. Long routes from many summer ranges come together at a few narrow passages before they spread out again into the sagebrush. Trappers Point is one of those passages. The corridor designation names 12 bottlenecks, and Trappers Point is the one listed by name in the Pinedale Roundup's report.
Researchers know this route well. Game and Fish and its partners put more than 400 GPS collars on Sublette antelope between 2002 and 2025, and monitoring continues, according to the Governor's release.
Every era has built on the same hill
The bottleneck came first, and people have kept building around it. The timeline below comes from the Sublette County Historical Society's Trappers Point Overlook page and recent state releases.
| When | What happened at Trappers Point |
|---|---|
| As long as 6,000 years ago | People hunted pronghorn at the site |
| 1833 to 1840 | Six mountain man rendezvous held on the Upper Green River Rendezvous grounds the hill overlooks |
| 1968 | Overlook established and dedicated during Green River Rendezvous Days |
| 1992 | Archaeological site found during US 191 construction |
| 2007 | Trappers Point Archeological Site listed on the National Register of Historic Places |
| 2012 | Two overpasses, six underpasses and 24 miles of 8-foot fence completed along US 191 |
| July 12, 2018 | Overlook re-dedicated with restored monument and new signs |
| June 26, 2026 | Sublette Antelope Migration Corridor designated at Trappers Point |
| Summer 2027 | 1.4-mile fence extension scheduled for completion |
The Historical Society owns and manages the 10-acre overlook. It describes the site as the meeting point of three major historical activities: the fur trade rendezvous, the pronghorn archaeology and the Green River Drift cattle operations. Ancient hunters picked this ground for the same reason highway engineers did. The animals reliably pass through it.
What the overpass proved
The 2012 project tested how firmly the pronghorn stick to their path. A WYDOT-funded study of the US 191 crossings published in 2015 counted 19,290 pronghorn and 40,251 mule deer migrations through the structures in the three years after construction. Pronghorn made 93 percent of their crossings over the highway instead of under it. The study found wildlife-vehicle collisions on that stretch fell by about 81 percent. Game and Fish says the Trapper's Point overpass was designed for pronghorn and that mule deer and elk use it as well.
The work is still growing. On October 5, 2026, Game and Fish reported that its commission and the WYDOT Commission had approved money for 1.4 more miles of 8-foot fence along US 191 near Pinedale. The new fence will steer wildlife toward the overpass and keep animals off a high-speed section of highway. It is the first project paid for with revenue from Wyoming's Wildlife Conservation License Plates. This extension is aimed mostly at mule deer, because the site sits near the Sublette Mule Deer Migration Corridor and crucial mule deer winter range. "We see the most wildlife collisions in this area during the winter," said Jill Randall, the department's Pinedale Region migration coordinator, in the Game and Fish release.
Wyoming drivers are paying for it. Game and Fish says the state has issued more than 8,700 conservation plates since 2019, and plate sales plus other driver donations have raised $3.4 million for wildlife projects statewide. Construction on the extension is set to finish next summer.
What the designation covers
The 2026 designation limits development. It does not limit visitors. The Pinedale Roundup reported that it bars new surface development on public land at the bottlenecks, including Trappers Point. It also bans any activity that needs a state permit there during the spring and fall migrations. Busy areas outside the bottlenecks require consultation with Game and Fish before development is approved. Protection is voluntary where pronghorn traffic is moderate or low, and private land is exempt. Game and Fish's corridor page says ordinary public-land recreation that does not need a special-use permit is not restricted by designation.
Angi Bruce, director of Game and Fish, called it "the first designated antelope migration corridor in the nation." The 11-member local working group chaired by Sweetwater County Commissioner Robb Slaughter spent six months on it before the Governor signed off.
The fall window is short
Spring and fall migrations run on very different schedules, and fall is the faster one. The newest USGS volume on Western ungulate migrations gives the Sublette herd's median fall migration as running from October 11 to October 29, with an average of 24 days on the move. In spring, the median runs from March 23 to May 3 and averages 40 days. These figures describe the whole herd's travel time. They are not a schedule for the overpass itself. Game and Fish notes that peak-use periods vary by location within a corridor and can shift with each year's weather.
This Thursday falls near the end of that median window. Any herds still moving now are the later part of the fall movement. In October 2019, Pinedale Online described the fall migration as already several weeks along. It reported that colder weather and late-fall snow push bigger herds down the valley toward their winter range. A storm over the Upper Green is a better cue than the calendar.
Herd sizes may also run smaller than older residents remember. Game and Fish's 2026 hunt forecast says the northern Sublette herd still shows the effects of the 2022–23 winter.
The same weather brings the cattle down. Pinedale Online described cattle coming out of the Upper Green during the Green River Drift alongside the pronghorn. Cowboys move the cattle along drift fences toward home ranches down the valley, usually in the morning. An early drive out of Cora on a cold morning can show you both.
Getting onto the hill
The Historical Society's directions to the Trappers Point Overlook start from Pinedale. Cora residents can begin at step two.
- Drive 5 miles west of Pinedale on US 191 to Cora Junction.
- Turn south on East Green River Road.
- After about 200 yards, turn right at the Trappers Point sign.
- Walk a quarter mile up the hill to the overlook.
From the top you can see the overpass, the Rendezvous grounds and the drift country, with signs explaining each. The walk also keeps you well away from traffic on US 191.
If you would rather drive, Pinedale Online reported that herds can often be seen along the Cora Highway, WY 352, toward Green River Lakes. They also show up on East Green River Road between US 191 and Highway 351. The same report asks viewers to watch from a distance and stay out of the animals' path. It notes that pronghorn feel less stress when people stay in their vehicles to watch or take photos. Those two roads are part of everyday driving for anyone who lives in Cora, so you may see herds on a normal trip to Pinedale this week.
If you want a pronghorn property near the Upper Green, or a place where the Drift passes the fence line, Janelle Villalba knows this ground and can help you find land that suits you and the herds that cross it. Reach out when you're ready to start, or for a free valuation of the property you already have near Cora Junction.
