Research Article

The Bitterroot Crossing: The Most Perilous Passage

Stephen E. Ambrose National Geographic 2003
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Ambrose reconstructs the expedition’s eleven-day crossing of the Bitterroot Mountains via the Lolo Trail in September 1805, widely regarded as the most physically demanding and dangerous segment of the entire Lewis and Clark journey. The article draws on journal entries from multiple expedition members to document the extreme conditions: deep snow, fallen timber, steep terrain, near-starvation (the party was reduced to eating candle tallow and horse meat), and the physical collapse of several members. Ambrose analyzes the critical role of Old Toby, the Shoshone guide who led the party over the mountains but occasionally lost the trail, and the expedition’s near-miraculous arrival in the Weippe Prairie, where the Nez Perce provided life-saving food. The article places the Bitterroot crossing in the context of the expedition’s overarching challenge: the utter failure of the imagined easy portage across the Continental Divide, which Jefferson and Lewis had anticipated based on incomplete geographic knowledge.

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