Centennial Trail South


The 2016 acquisition of Centennial Trail South extends the current Centennial Trail from the City of Snohomish south to Woodinville in King County. This 12 mile rail-with-trail corridor will complete the regional trail through Snohomish County, from the Skagit County line to the King County line and will eventually connect to the King County trail system further south.

The new trail section will be similar to the existing Centennial Trail, and will accommodate both pedestrian and bicycle usage. The proposed alignment traverses areas with steep cross slopes, bridges, trestles, sloughs and other natural features which complicate construction. As a result, trail construction is anticipated to take place in phases.


The Eastside Rail System was built in the late 1800s and early 1900s. In 2009, Burlington Northern and Santa Fe Railway (BNSF Railway) was the property owner and, sold the eastside railroad right-of-way and assets extending from the Snohomish River south to Renton, including the Redmond spur, to the Port of Seattle. In a separate transaction, BNSF Railway sold the freight rail operating rights extending from the Woodinville wye north to the BNSF Railway main line near Snohomish to a third party. Subsequent to these sales, various jurisdictions in King County with interest in the right-of-way purchased portions from the Port of Seattle.

In March 2016, the Snohomish County Council approved a purchase and sale agreement to acquire the railroad right-of-way and improvements south of Snohomish to the King County line from the Port of Seattle. County acquisition was completed in 2016.

Rail Operations

Dual use is anticipated within the 100-200 foot wide corridor as freight trains continue to serve businesses in the area. Recreational rail and ultimately passenger use may also occur.


The right-of-way south of the Woodinville wye has been railbanked (a voluntary agreement between a railroad company and a trail agency to use an out-of-service rail corridor as a trail until rail service in the corridor is reinstated).


Funds have been secured to conduct engineering studies and complete a preliminary design for the entire corridor. The initial design is complete with public outreach and environmental document preparation anticipated to occur in 2021. Permitting stages and final design for the first phase will soon follow with construction to begin once construction funding is secured. Exact scope of the first phase has not yet been determined.


  • 2016-2022: Engineering studies, public involvement, preliminary design, survey, and environmental review process
  • 2022-2024: Construction to occur in phases, pending funding availability

The process of developing road and trail projects takes several years. Many factors must be considered, including: location of homes; public right-of-way; stormwater runoff, drainage and water quality; wetlands and buffers; hilly terrain; sight distance; soils; traffic volumes; accident history; vehicle and pedestrian access; location of utilities; and information that residents provide about the area.

Environmental Review

Snohomish County will complete an environmental review of the proposed project area in compliance with the State Environmental Policy Act (SEPA).

Additional Information