Snohomish County Centennial Trail, Rail trail in Snohomish County, United States.

The Snohomish County Centennial Trail is a 30-mile paved rail trail from Snohomish to the Skagit County line, following the Seattle, Lake Shore and Eastern Railway corridor. Its 10-foot-wide asphalt surface runs beside a 6-foot-wide equestrian path, passing trailheads such as Pilchuck, Machias, Rhododendron and Nakashima Heritage Barn.

The trail follows the Sumas Branch right-of-way of the Seattle, Lake Shore and Eastern Railway, built in 1889 to link Seattle with Canada and carry timber, mail and passengers. After Northern Pacific and Burlington Northern ownership, the Snohomish–Lake Stevens section was abandoned in 1987. The rail trail was conceived in 1982 and its first segment opened in 1989, Washington's centennial year; the last stretch to the Skagit County line opened in 2013.

The trail links several small towns and allows visitors to move through the rural landscape of Snohomish County while experiencing how the communities function and connect. Interpretive signs along the way tell stories about the railroad heritage that shaped these places and their role in regional development.

The trail runs 30 miles from Snohomish to the Skagit County line, with trailheads spaced along the route, including Machias, 20th Street, Rhododendron, Lake Cassidy Wetlands Park, 84th Street, Armar Road and Nakashima Heritage Barn. The paved surface is 10 feet wide, with a separate 6-foot equestrian path beside it. The route passes under U.S. Route 2 near the Pilchuck trailhead and under State Route 92 near Lake Stevens.

The trail's equestrian path is a separate 6-foot-wide natural surface running beside the 10-foot paved route, so horses never share the asphalt with cyclists and walkers. The corridor follows the former Sumas Branch railbed of the Seattle, Lake Shore and Eastern Railway, built in 1889.