 Between Orchards and Amboy, SR 503 was designated as the "Lewisville Highway", serving historic Lewisville Park.SR 503 Spur, known locally as the Lewis River Road, begins its route at an intersection with SR 503 east of Yale and north of the Yale Bridge.The highway travels northeast along Yale Lake through a forested region of Cowlitz County, passing Yale Park and the community of Cougar.