His route and travel method likely took him on a stagecoach over Donner Summit and east along the well-traveled Humboldt River Trail to Winnemucca, Nevada, then north to the U.S. Army's Camp McDermitt at the Oregon border. Passing the camp in rugged terrain, the men reached an Owyhee River crossing at present-day Rome, Oregon, where an apparent accident occurred and Charbonneau went into the river. The accident's cause is unknown, but there are several possibilities. He may have been on a stagecoach operated by the Boise-Silver City-Winnemucca stage company that began its route in 1866 out of Camp McDermitt and in crossing the river, the coach sank. Or he may have been on horseback and fallen off the river bank or slipped out of the saddle while crossing. The Owyhee River in snow melt may have turned into whitewater. Other possibilities are he was injured on the land journey, inhaled alkali dust, or fell ill from drinking contaminated water.