Clayton is an unincorporated community in Stevens County, Washington, United States. It is located along U.S. Route 395 4.5 miles (7.2 km) northwest of Deer Park, and has a post office with ZIP code 99110. Clayton was founded in 1889 and was named for nearby clay deposits. The Washington Brick Company was established in 1893. It, along with most of the town, was lost to a catastrophic fire in 1908, but the town rebuilt, and the new Washington Brick, Lime, and Sewer Pipe company became noted for its high-quality products, including beautiful decorative terra cotta panels, which were crafted largely by skilled artisans who had immigrated to Washington from northern Italy.Clayton was listed as a census-designated place for the 2010 census and has a population of 443. The median household income is about $32,000. The average annual temperature is about 47 °F, which is approximately 7 °F lower than the average temperature throughout the United States. The average age of residents is 28 years old, 9 years younger than the U.S. average.
This part of old U.S 395 follows the route of PSH 3. This route followed Interstate 82 from Ellensburg to the Oregon State line (concurrent with U.S. Route 97 from Ellensburg to Union Gap and U.S. Route 410/12 from Union Gap to the Tri-Cities), U.S. Route 410 (now U.S. Route 12) from the Tri-Cities to Clarkston, U.S. Route 195 from Clarkston to Pullman, SR 27 from Pullman to Oaksedale, US 195 from Oakesdale to Spokane, U.S. Route 2 from Spokane to Mead and U.S. Route 395 from Mead to the U.S.-Canada border. Spurs extended along I-82/, SR 125 and SR 129 from Tri-Cities, Walla Walla and Clarkston to the Oregon State Line. This route was also known as the "Inland Empire Highway" and crossed the first, and for a time, the only highway bridge over the middle Columbia River. That bridge was located between the towns of Kennewick, WA and Pasco, WA
This cache is easy to get to. There is plenty of parking.
Extra Credit: If you head down Railroad Street, you will drive by old stores, houses, and road materials. Railroad Street turns toward Deer Park, but if you turn on the road before the new highway you will drive down along BNSF traintracks, and find yourself facing new U.S 395.