Washington is likely to get a new congressional district after the 2010 Census. So where would a new Tenth congressional district go?
The only geographically logical place is a district centered on Olympia, now a part of the Third. Adding an district inescapably causes dislocations, but as in this case, offers a chance for improvement in the form of more logically coherent districts.
Population growth in Washington was enough that even with a tenth district, the population per district will rise slightly from 655,000 to 673,000. Unlike in some earlier decades, eastern Washington has grown as well, so both the Fourth (Republican Doc Hastings) and Fifth (Republican Cathy McMorris Rodgers) districts have to contract, the Fifth will probably by losing Okanogan and Adams counties to the Fourth, and the Fourth may well lose Klickitat and 117,000 or so people from Yakima to the Third. Sorry, Yakima County, there is no escape from this dislocation.
In turn, the Third (newly elected Republican Jaime Herrara) has to change a lot, having to shed Lewis, Pacific. Wahkiakum, and Thurston, even probably a tip of Cowlitz. So the Third becomes an east-west Columbia River district, more geographically logical than before.
Such shifts clearly set up Thurston (Olympia) as the core of a district, dispossessed from the Third district. The new Tenth, with Lewis, Pacific, Wahkiakum, and Thurston counties on its south, would need to add the Olympic peninsula counties of Clallam, Jefferson, Mason, and Grays Harbor, plus 80,000 or so, probably from Pierce County rather than from Kitsap. Such a Tenth makes a really sensible Pacific and far western Washington district of similar history and geography.
In the north the Second district (Democrat Rick Larsen) has to shed much of Snohomish County, retaining only 260,000 or so, increasing the Snohomish County share of the First district (Democrat Jay Inslee) to 450,000.
The above changes are more or less inescapable, simply from the geography of population change. The disposition of the five metropolitan core districts (1, 6, 7, 8, and 9) is less obvious and subject to greater political mischief. From a geographic community of interest perspective, the Seventh (Democrat Jim McDermott) needs to change only slightly. The Sixth (Democrat Norm Dicks), having lost the peninsula counties, might logically combine most (or all) of Kitsap and western Pierce, including Tacoma. This in turn makes possible a somewhat better configuration of the Eighth (Republican Dave Reichert) to include all of eastern King County, perhaps, and Ninth (Democrat Adam Smith) districts.