I am asked this question a lot. I’m asked it most often by people who have spent most of their lives in the Tri-Cities, and they don’t understand why we’ve suddenly been ‘discovered’. There is so much development going on, and we still have land readily available, no wonder people are moving here. We had a net gain of 5,275 people in Benton County over the period of 2000-2005. Franklin County experienced a net gain of 4,099 people over the same period of time. King County LOST over 49,000 people, but it appears as if some moved to Snohomish (gained over 11,000 people) or Pierce (over 15,000 people moved in) counties. It’s really interesting to see the ebb and flow of the state’s population centers. The map in the link can take you to other states, btw. Have fun looking!