Seattle Hill Road

Ground Breaking Event

Join Snohomish County Public Works to celebrate kicking off construction on 
Seattle Hill Road. The project includes adding a center turn lane, bike lanes, curbs, 
sidewalks, drainage improvements and re-aligning the road for improved line of sight. Speakers include Public Works Director Steve Thomsen, Executive Director Ken Klein 
and Councilmember Terry Ryan.

When: April 20, 2017 from 1:00 p.m. to 2:30 p.m.
Where: Triway Grange Hall, 3509 Seattle Hill Road,
Mill Creek, WA 98012
What: Seattle Hill Road Ground Breaking Event

March 2017 Update

Construction is scheduled to begin on April 10, 2017. Intermittent single-lane closures and lane shifts will be required for this project. See below for more details on traffic impacts.


Snohomish County plans to improve Seattle Hill Road between 132nd Street SE and 35th Avenue SE.
Project details include:
  • Widen the road to three lanes including a center turn lane 
  • Add bike lanes, curbs and sidewalks 


  • 2017 – Roadway construction will begin April 10, 2017 at the south end of the project. The work is scheduled to continue through the summer of 2018.
  • 2016 to 2017 – Puget Sound Energy (PSE), Silver Lake Water District, BP, and Snohomish PUD scheduled to move necessary utilities to accommodate widening of the road.
  • 2013 – Environmental review 
  • February 28, 2013 – Public open house at Mill Creek Elementary


Traffic Impacts

  • Intermittent single-lane closures will occur throughout construction with flaggers directing traffic. 
  • Commuters traveling through the area should expect delays of up to 20 minutes. 
  • Two 3-day full-road closures will be required in the summer.
  • One additional week-long full-road closure will also occur.
  • Detour signs will be used to notify corridor users when the closures will be in affect and the detour routes.


The estimated project construction cost is $9.2 million. Approximately 44 percent of the construction cost is from Federal Surface Transportation funding, distributed by the Puget Sound Regional Council. An additional 44 percent is funded by the Washington State Transportation Improvement Board. The remaining construction funding is provided by the City of Mill Creek and Snohomish County.

Such funding speaks to the significance the project will have on the improvement of vehicular and pedestrian safety and congestion in the area.

Environmental Review

An environmental review of this project was completed in compliance with the State Environmental Policy Act (SEPA). The SEPA documents can be reviewed below. The comment period for this project closed on April 7, 2013. If you have questions please contact Mary Auld at 425-262-2460, via email, or by mail: Mary Auld, Snohomish County Public Works, 3000 Rockefeller M/S 607, Everett, WA 98201

Available Documents:
The process for developing road projects take several years; many factors must be considered. These factors include:
  • Accident history
  • Critical area regulations (CAR)
  • Design standards
  • Information that residents provide about the area
  • Location of homes and public right-of-way
  • Location of utilities
  • Sight distance
  • Soil compaction
  • Terrain
  • Traffic volumes
  • Wetlands, stormwater runoff, drainage, and water quality

Public Meeting

Snohomish County Public Works held a public meeting on February 23, 2017 to discuss three projects in this area. The projects were Seattle Hill Road, 35th Avenue SE, and 156th Street SE. Staff was available to answer questions about the construction on Seattle Hill Road, review proposed road improvements to the section of 35th Avenue SE, and gather feedback on potential designs for the 156th Street SE project.

Other Projects in the Area

In addition to the Seattle Hill Road project, the county is working on improvements to other nearby corridors including: