Lisa built a trading-post, Fort Manuel, at the junction of the Big Horn and Yellowstone Rivers, about two hundred miles southeast of the Yellowstone Park. From here, with a thirty-pound pack and rifle, Colter set off alone on a thousand-mile journey into the wilderness to tell the surrounding Indian tribes of this new trading-post.
He traveled a few hundred miles to the southwest without notable adventure. We now marvel at the results of this journey, for its discoveries put Colter in the front rank of geographical explorers on the American continent. He discovered the Wind River Range, Union Pass, Jackson Hole, Teton Pass, Pierre's Hole, and the Grand Teton. He was the first to see the headwaters of those two great rivers the Green Fork of the Colorado and the Snake Fork of the Columbia. These discoveries might well have been enough for any one man, but his greatest discovery was still before him.
Colter was with a band of Crows near Pierre's Hole when it was attacked by marauding Blackfeet. Of necessity Colter fought with the Crows, who were victorious. The Blackfeet blamed Colter for their defeat, and from this incident may have arisen the long-continued hostility of the Blackfeet tribes against the whites.
Again alone, Colter set forth from Pierre's Hole, St. Anthony, Idaho, and traveled straight across the mountains to Fort Manuel. A wound in the leg, which he had received in the fight with the Blackfeet, was not yet healed. The direct route that he took for his return may have been chosen as the shortest, but most probably was selected in order to avoid the Blackfeet.
The crowning achievement of this remarkable journey was the discovery and traversing of the Yellowstone wonderland. His course took Colter diagonally, from southwest to northeast, across what now is the Yellowstone National Park. He probably passed along the west shore of Yellowstone Lake, and may have followed the Yellowstone River from the lake to the falls. He saw numerous geysers, hot springs, paint-pots, and possibly Sulphur Mountain. He noted that numerous rivers had their sources in the Park and flowed from it in all directions, thus justifying the Indian name for the region, "Top of the World." After crossing Mount Washburn he probably forded the river near Tower Falls and then followed the east fork of the Yellowstone.
Colter arrived safely at Fort Manuel after a journey of about three hundred miles from Pierre's Hole and a round trip of about eight hundred miles. Aside from its geographical value, this was a remarkable wilderness achievement.
A little later came the most extraordinary chapter of Colter's adventurous life. In 1809, with a companion named John Potts, he was trapping beavers near the Three Forks of the Missouri. They were rowing up a small stream that flowed into the Jefferson River, the most western of the forks. At a point on this stream about five miles from the Jefferson, they heard a great trampling. High banks and brushwood shut off their view.
Presently about five hundred Blackfeet appeared on the banks and ordered them to come ashore. Escape was impossible. The two men had the hardihood to throw the beaver-traps overboard, hoping to recover them later. As the canoe touched the shore, an Indian snatched Potts's rifle from him. Thereupon Colter sprang ashore, wrested the rifle from the Indian, and handed it to Potts who immediately pushed off into the stream. Colter told him to come back and not to try to escape. An arrow whizzed by Colter, and Potts fell back in the canoe, crying out, "I'm done for!" as he shot an Indian dead. In an instant his body was filled with arrows.
The Blackfeet seized Colter and stripped him naked, then discussed methods of torturing him to death. They decided to set him up for a target, but the chief interfered—that was not exciting enough for him. Seizing Colter by the shoulder, he asked him if he could run fast. The question was greeted with howls of delight by the Blackfeet.
The chief led Colter out on the prairie about three hundred yards from the band, pointed in the direction of the Jefferson River, told him to save himself if he could, and cast him loose. Colter ran, the Blackfeet whooped and pursued, and the race for life was on.