 A spur route, established in 1991, travels northeast into the Gifford Pinchot National Forest along Yale Lake, serving the community of Cougar.SR 503 begins concurrent to SR 500 at an intersection with Fourth Plain Boulevard in Orchards.The two highways travel north on the four-lane 117th Avenue through Orchards until SR 500 turns east onto Padden Parkway, while SR 503 continues north into rural Clark County, passing Prairie High School.