Lewis County was established March 3, 1911 with its county seat at Nezperce.  The County was named for Meriwether Lewis of the Lewis and Clark Expedition.  The Nez Perce Indians made this area their home and knew no whites until the Lewis and Clark expedition.  The expedition spent a month in the Clearwater River Valley near the town of Kamiah on its return from the Pacific Coast in May 1806.