- Lewiston is the county seat of and largest city in Nez Perce County, Idaho. It is the second largest city in the Idaho Panhandle region behind Coeur d’Alene. It sits across the river from Clarkston, Washington. In 2020, Lewiston was home to 34,000 people. Like Pocatello, Lewiston has a strong working-class heritage. Industries related to timber and logging pursuits have long been key to the city’s economy. Because the Columbia and later the Snake River are navigable by some ocean-going vessels all the way to Lewiston, the city has the distinction of being Idaho’s only port city, and the furthest inland port in the western United States.