My hometown is actually Kennewick, one of the Tri-Cities. The other two are Richland and Pasco. These three communities are located at the confluence of the Snake and Columbia Rivers. Each of these cities began and grew from a different source. The oldest is Pasco and was a railroad town, Kennewick grew out of agriculture - particularly fruit trees and vineyards, and Richland - the youngest - was created by the federal government as part of the Manhattan Project during World War II.
The first book in this series is River Marked, Book 6 in the Mercedes (Mercy) Thompson series, by Patricia Briggs.
This series is probably best classified as urban fantasy. Mercy is a shapeshifter and works as a VW mechanic for a fae (fairy). The fae have come out and are placed on a reservation located in Walla Walla County. There is also a werewolf pack (which comes out in the series) that is located in Finley, an unincorporated community just to the east of Kennewick. Finally, there is a vampire seethe (or coven) in Richland.
River Marked takes place mainly just outside the Tri-Cities, in the Columbia River Gorge. Mercy gets married, goes on her honeymoon, and has to fight an ancient Native American evil. Mercy is half Native American, she believes she is half Blackfoot (or Blackfeet). There are supporting characters in this novel that are of the Yakama Nation.
Many of the sites featured in the book are centered around the Columbia River Gorge. They include Multnomah Falls in Western Oregon.
They went to Horsethief Lake to view the pictographs and petroglyphs there - in particular, She-Who-Watches.
When Mercy and Adam needed to get supplies and stock up, they went on to Hood River, Oregon
Mercy even gets into a fight with an otterkin at the Hood River WalMart. (Clean-up in women's apparel!)
An integral part of the book concerns the Native American mythology character of Coyote.
Mercy needs his help to fight the River Devil: