At Coupe A Jarcke, William Clark recorded the expedition's passage on August 9, 1804, when thick fog delayed travel until half past 7 o'clock, after which they proceeded under a gentle breeze, Clark walked on shore, saw an elk, crossed an isthmus of three-quarters of a mile to the river, returned to the boat, and camped on the larboard side above a beaver den amid very troublesome mosquitoes. On August 10, 1804, Clark's field notes showed the difficulty of navigating the expedition's three boats upriver past this place, which he identified as a point where the river cut through and shortened the river by several miles, turning a distance of three-quarters of a mile into thirteen miles around the bends. On September 5, 1806, during the return trip downriver two years later, the party again passed Coupee a Jacke, traveling much faster and camping in the area. These passages were part of the Lewis and Clark expedition, sent by President Thomas Jefferson in 1803 under Meriwether Lewis and William Clark to explore the newly acquired Louisiana Purchase, seek an all-water route to the Pacific Ocean, and make peaceable contact with Native peoples; the explorers left on May 14, 1804, reached the Pacific in November 1805, and returned to Saint Louis on September 23, 1806, after traveling more than 8000 miles in two years, four months and nine days.