The Marias River

Lewis found greasewood (Sarcobatus vermiculatus) when he passed below the Marias River a second time on July 20, 1806.

On June 3, 1805, at the confluence of the Marias River (near present day Loma) the Corps faced a navigational challenge. Lewis recorded his dilemma… "An interesting question was now to be determined; which of these rivers was the Missouri… the utmost circumspection and caution was necessary in deciding on the stream to be taken."

The expedition first spotted the long-tailed weasel in Montana near the mouth of the Marias River.

Lewis decided to travel up the Marias to determine whether or not it was the correct route, …"I now became well convinced that this branch of the Missouri had it's direction too much to the North for our rout to the Pacific." Although the enlisted men did not support his conclusion, they dutifully accepted their captain's decision. After caching items for their return trip, the Corps took a left turn and continued up the Missouri to the Great Falls and Lewis proved to be right.

The following are a few of the stops in the journey:

• White Cliffs
• Marias River
• Great Falls
• Headwaters of the Missouri
• Beaverhead Rock
• Travelers' Rest Westbound
• The Rocky Mountains
• Travelers' Rest Eastbound
• Return Across Montana
• The Voyage's End