Sandy River (Oregon) - Course

Course

Issuing from Reid Glacier on the southwest flanks of Mount Hood in the Cascade Range, the Sandy River flows generally west and then north for 56 miles (90 km) through Clackamas County and Multnomah County to the Columbia River at Troutdale. In its first 12 miles (19 km), the Sandy River flows across Old Maid Flat, north of Zigzag Mountain in the Mount Hood Wilderness of the Mount Hood National Forest. In this initial stretch near the headwaters, it receives Rushing Water Creek from the left, Muddy Fork from the right, then Lost Creek and Horseshoe Creek from the left, and crosses under Lolo Pass Road just before receiving Clear Creek from the right. At about 41 miles (66 km) from the mouth, the Zigzag River enters from the left near the unincorporated community of Zigzag. From here the river runs roughly parallel to U.S. Route 26, which is on its left for about the next 20 miles (32 km). Just below Zigzag, the Sandy River passes the unincorporated community of Wemme on the left.

At about 39 miles (63 km) from the mouth, the river receives Hackett Creek from the right, passes the unincorporated community of Brightwood shortly thereafter, and receives North Boulder Creek from the right. Barlow Trail County Park and remnants of the Barlow Road lie to the right along this stretch of the river. Between 38 miles (61 km) and 37 miles (60 km) from the mouth, the Salmon River enters from the left. Roughly 4 miles (6.4 km) later, Wildcat Creek enters from the left and then Alder Creek and Whiskey Creek, also from the left. The river passes the Marmot gauging station operated by the United States Geological Survey (USGS) in cooperation with Portland General Electric at river mile (RM) 29.8 (river kilometer (RK) 48.0). The unincorporated community of Marmot lies to the right of the river on a ridge—the Devil's Backbone—separating the Sandy River from the Little Sandy River to the north.

About 4 miles (6.4 km) below the Marmot gauge, the river receives Badger Creek from the left. It passes under Ten Eyck Road about 24 miles (39 km) from the mouth, flowing by the city of Sandy on the left, shortly thereafter and receiving Cedar Creek, home of the Sandy Fish Hatchery, from the left. At about 22 miles (35 km) from the mouth, the river turns away from Highway 26 and flows generally north-northwest for the rest of its course. About 3 miles (4.8 km) further downstream, the river passes Dodge Park on the right, receives the Bull Run River from the right and passes a second USGS gauge at RM 18.4 (RK 29.6).

Shortly thereafter, Walker Creek enters from the right. Between 17 miles (27 km) and 16 miles (26 km) from the mouth, the Sandy River enters Multnomah County, curves back into Clackamas County, and re-enters Multnomah County. About 1 mile (1.6 km) further downstream, Bear Creek enters from the left, and the river flows around Indian John Island.

Soon Trout Creek, Gordon Creek, and Buck Creek all enter from the right as the river winds through Oxbow Regional Park between 14 miles (23 km) and 11 miles (18 km) from the mouth. Passing Camp Collins about 1 mile (1.6 km) later, the river receives Big Creek from the right. Dabney State Recreation Area is on the right about 4 miles (6.4 km) later. Lewis and Clark State Recreation Site is on the right and Troutdale on the left at about 3 miles (4.8 km) from the mouth, where Beaver Creek enters from the left. Shortly thereafter, the river passes under Interstate 84 and flows by Portland-Troutdale Airport, which is on the left about 2 miles (3.2 km) from the mouth. The Sandy River then joins the Columbia River about 120 miles (190 km) from where the larger river enters the Pacific Ocean. The confluence is about 14 miles (23 km) east of Portland, near the lower end of the Columbia River Gorge.