Whether Colter crossed the Continental Divide at Togwotee, at Union Pass to the south, or somewhere else entirely is the single most-debated detail of the route. Burton Harris (1952) read the evidence for Union; Mattes (1962) preferred Togwotee. We render this as a low-confidence segment. The modern paved auto route uses Togwotee because Union has no road.
Togwotee Pass takes its name from a Sheep Eater (Tukudika) Shoshone guide who worked with the 1873 Hayden Survey. The pass and the country around it were known to Shoshone, Bannock, and Crow long before any non-Native named them. The Wind River–Togwotee–Jackson Hole corridor sits adjacent to the modern Wind River Reservation (Eastern Shoshone + Northern Arapaho).
By the 1820s the country west of Togwotee was prime trapping ground, drawing fur-trade rendezvous to Pierre's Hole and the Green River. Colter's traverse predates the rendezvous economy but seeded the geographic knowledge that drove it.
The two candidate passes are Togwotee (today's US-26/287, 9,658 ft) and Union Pass (no paved road, 9,210 ft). Both connect the Wind River drainage with the Snake/Jackson Hole drainage. Mattes argued Togwotee on the basis of Clark's 1814 map geometry; Harris argued Union on the basis of the easier winter approach. The argument has never been settled and may never be — Colter left no written record.
Almost everything specific about this segment. Which pass. What month. Whether he traveled with a Crow guide on this leg or alone. Whether he doubled back or pressed through. This is the segment where the 'probable' framing matters most.
Togwotee is open year-round on US-26/287 (a major Wyoming highway). The summit area has trailheads (Brooks Lake, Continental Divide Trail), pullouts, and Togwotee Mountain Lodge as a lodging anchor. The pass is heavily used in winter for snowmobiling. The 1807 reconstruction is rendered on the map; the modern crossing is what visitors will actually use.
Phase 3: 360° at the Togwotee summit pullout; alternate set at Union Pass for the comparative view; commentary segment naming the Harris/Mattes argument plainly.
Sources & attribution: Burton Harris (1952) · Merrill J. Mattes (NPS, 1962) · USFS Bridger-Teton NF · Wyoming Department of Transportation