Salmon River, Brook in Polk County, United States

Salmon River is a roughly 24-mile (39 km) stream that rises near the Lincoln–Polk county line and reaches the Pacific about 4 miles north of Lincoln City, below Cascade Head. Much of its course runs through the Siuslaw National Forest, and Oregon Route 18 follows it for 19 km through the H. B. Van Duzer Forest State Scenic Corridor, partly old-growth Douglas fir. Its mouth forms a 177-hectare wetland behind a sandbar.

The Salmon River drains a course of about 24 miles (39 km) from the slopes of Saddle Bag Mountain, on the Lincoln–Polk county line, to the Pacific just south of Cascade Head. It was long treated as the boundary between the Northern and Central Oregon Coast Range. Since 1935 the H. B. Van Duzer Forest State Scenic Corridor has protected old-growth Douglas fir along 19 km of Route 18 beside the river.

The river marks the boundary between the Northern and Central Oregon Coast Range, and its name distinguishes it from the Salmon River that rises on Mount Hood. Near Otis a hatchery releases thousands of chinook and coho salmon each year, and the lower course is fished for salmon and rainbow trout.

Oregon Route 18 follows much of the river, running 19 km through the H. B. Van Duzer Forest State Scenic Corridor, where old-growth Douglas-fir stands beside the road. The river enters the Pacific about 6 km north of Lincoln City, just south of Cascade Head.

The river's mouth, about 6 km north of Lincoln City, is blocked by a sandbar that forms a wetland of roughly 177 hectares. This estuary shelters waterfowl such as belted kingfishers, common mergansers and buffleheads, plus northern harriers and bald eagles.