Gates of the Mountains: Lewis and Clark on the Missouri

On July nineteenth, eighteen oh five, Meriwether Lewis wrote an entry in his journal that survives as one of the most vivid passages in the entire record of the Corps of Discovery. The expedition had been pushing up the Missouri River for weeks, and now, north of what would become Helena, the channel entered a limestone canyon whose walls rose nearly twelve hundred feet straight from the water.

Lewis wrote: "from the singular appearance of this place I called it the gates of the rocky mountains." The cliffs pressed so close on both sides that the boats barely had room to pass. The current ran fast. The rock faces loomed overhead and closed behind the party as they moved through, so that at every moment the way forward seemed to be shutting and the way back seemed already sealed.

The canyon Lewis described is today called the Gates of the Mountains, a name taken directly from his journal entry. It lies roughly twenty miles north of Helena, where the Missouri cuts through the Big Belt Mountains in a gorge that the expedition could not have gone around and could not easily have portaged. They had to go through.

Wildfire has swept these forested slopes before, most famously the deadly Mann Gulch fire of nineteen forty-nine, and the limestone cliffs still stand bare above a recovering landscape. Boat tours still run the canyon from a landing near the canyon, following the same channel Lewis and Clark navigated by oar and pole.

The expedition spent less than a day moving through the gorge before the walls opened and the river widened again into the valley. Lewis did not linger to describe it further. He had a continent to cross, and the Rockies were still ahead.