The Engineering Division is managed by the County Engineer and fulfills all of the statutory requirements of the county road engineer under RCW 36.75 and WAC Title 136. In addition, the engineering program provides broad civil, structural, and mechanical engineering support to other county departments and other public agencies including the Town of Friday Harbor, Port and Fire Districts, Parks and other junior taxing districts.
The engineering program oversees most large scale construction projects, all road, bridge, dock, and marine facility construction and maintenance.

The program provides long-range transportation and infrastructure planning, development reviews, database management, planning review and project management services.