 SR 100 begins at an intersection with US 101 in Ilwaco as the highway turns north onto 1st Avenue towards Seaview . The highway , part of the Lewis and Clark Trail Scenic Byway , travels west on Spruce Street through an intersection with the clockwise terminus of SR 100 , on 2nd Avenue , and continues towards the Pacific Ocean on North Head Road . SR 100 turns south along the Pacific coast past North Head Lighthouse and into Cape Disappointment State Park on Robert Gray Drive . The highway intersects its spur route that travels south on Fort Canby Road towards Coast Guard Station Cape Disappointment . SR 100 turns north and travels into Ilawaco along Baker Bay and the Columbia River before it ends at an intersection with SR 100 a block from its terminus at US 101 . 
