Lewis County is a county in the state of Washington, being of medium size both in area and population. It lies about halfway between the cities of Portland, Oregon and Seattle, Washington, which is where its largest city, Centralia gets its name.
To explain Lewis County, a note on the geography of Oregon and Washington must be made. Between the Coast Range and Cascade Mountains, there is a long basin, running from the city of Eugene, Oregon all the way up to Vancouver BC. The Puget Sound is actually just a part of this basin that is under water. But in Oregon, south of the Columbia River, the basin is the broad, wide Willamette Valley, with rich soils perfect for farming. As it enters Washington, it becomes much more narrow and hilly. That is why the game was called Oregon Trail: early settlement in the area was in the easy farmlands of Oregon, where Washington was more focused towards timber and shipping, and truly came into its own with manufacturing during World War II. However, in Lewis County, the terrain looks more like the Willamette Valley than it does like the hilly lands of Western Washington. This is because a river, the Chehalis, has created a broad, flat and fertile flood plain that winds its way through most of the populated part of the county. Although some of the county is in the Cascade Range, and mining and timber were important, the county was much more oriented towards farming than the surrounding areas.
And this explains much of Lewis County's past and present demographics. To the north and south, the Seattle metro area, and the Portland metro area (parts of which extend into Southwest Washington) attracted manufacturing jobs, and the attendant demographic diversity, Lewis County was mostly agricultural. Because of its rural nature, and lack of a manufacturing base with its attendant unions, Lewis County is much more socially and politically conservative than the rest of Western Washington. In 2008, it was the only county in Western Washington to vote for John McCain. Although some of its reputation is probably undeserved, the entire area is seen as a type of flyover country for those traveling between Portland and Seattle. Whether the tides of gentrification and the suburbanization will turn Lewis County into a smaller Olympia or Vancouver remains to be seen, but for now it is a slice of the remaining rural in the rapidly developing realm of Western Washington.