In 1839 George Simpson, the governor of the Hudson's Bay Company, directed Pierre-Chrysologue Pambrun, the HBC clerk in charge of Fort Nez Percés (Walla Walla), to scout out a trail over the Cascade mountains from Walla Walla to Fort Nisqually at the southern tip of Puget Sound, where Simpson planned to settle a group of families from Red River Colony (today's Winnipeg, Manitoba). Accompanied by Cornelius Rogers, an associate of Dr. Marcus Whitman at Waillatpu mission, Pambrun crossed Naches pass. In the summer of 1841 Lieutenant Charles Wilkes of the United States Exploring Expedition directed Lieutenant Robert E. Johnson to proceed east over the Cascades via the Naches Pass. The expedition followed the existing Indian trail around the northern flank of Mount Rainier and over the pass. They proceeded to Fort Colvile and Fort Okanogan east of the mountains.