When Captain Meriwether Lewis and his men arrived in the Jefferson River Valley in August 1805, they explored the tributaries of the Jefferson River, today's Beaverhead River, which was named after President Thomas Jefferson. They named its tributaries Philanthrophy and Wisdom in homage of the President's character; these rivers are now referred to as the Ruby and Big Hole respectively. During this exploration, Captain Lewis made a broad loop south of present-day Twin Bridges, observing the Ruby and Beaverhead Rivers. He walked about 15 miles up the Big Hole River before returning to his men, and after this journey he was convinced that the Jefferson River was the route to travel.