Roads Snohomish County has two
Interstate Highways, one
U.S. route, and several
state routes that connect it to other areas. The county's main highway is
Interstate 5 (I-5), which runs north–south for and travels through several major cities. Other major routes are primarily north–south routes, including
State Route 9 on the east side of the urbanized area;
State Route 99 to the west of I-5; and
State Route 527 in Mill Creek and Bothell. The only complete east–west route is
U.S. Route 2. •
Interstate 5 •
Interstate 405 •
U.S. Route 2 •
State Route 9 •
State Route 92 •
State Route 96 •
State Route 99 •
State Route 104 •
State Route 203 •
State Route 204 •
State Route 522 •
State Route 524 •
State Route 525 •
State Route 526 •
State Route 527 •
State Route 528 •
State Route 529 •
State Route 530 •
State Route 531 •
State Route 532 The county government maintains approximately of roads and 200 bridges. The countywide numbered street grid originates in Everett and was implemented beginning in the 1970s during the rollout of the
911 emergency phone number system. By the late 1990s, some roads had reverted to their historical names—either officially or by using commemorative signs—due to local backlash.
Public transportation Snohomish County is served by several
public transit systems that connect to each other at regional hubs, including
Everett Station and
Lynnwood City Center station. The primary provider is
Community Transit, which operates local service within the county (apart from the city of
Everett) and commuter service to the
Boeing Everett Factory and
Downtown Seattle.
Sound Transit, a regional transit agency, provides
light rail,
commuter rail, and
express bus services that connect to regional destinations in Seattle and
Bellevue. Other providers include
Everett Transit, a municipal system serving the city of Everett;
Island Transit, which connects
Camano Island to Stanwood and Everett; and
Skagit Transit, which operates an inter-county route from Everett to
Mount Vernon. The regional
Link light rail system was extended into Snohomish County with the opening of the
Lynnwood Link Extension on August 30, 2024, which includes stations in Mountlake Terrace and Lynnwood on the
1 Line. The project was approved in a 2008 ballot measure and began construction in 2019. An
extension to Everett with six or seven stations was approved in the regional
Sound Transit 3 ballot measure in 2016 and is expected to open between 2037 and 2041. Community Transit operates a
bus rapid transit network called
Swift with three lines : the
Blue Line, which opened in 2009 from Everett to
Shoreline along State Route 99; the
Green Line from the Boeing Everett Factory to
Bothell via Airport Road and
State Route 527; and the
Orange Line in Lynnwood and Mill Creek, which opened in 2024. A fourth line, the
Gold Line, is planned to open by 2029 and connect Everett to Marysville and
Smokey Point. Sound Transit also runs four daily
Sounder commuter trains at peak hours between Everett Station and
King Street Station in Seattle, stopping at
Mukilteo and
Edmonds. Intercity rail service is provided by
Amtrak, which has two lines operating within Snohomish County:
Amtrak Cascades between Seattle and
Vancouver,
British Columbia, stopping in Edmonds, Everett, and
Stanwood station; and the
Empire Builder between Seattle and
Chicago,
Illinois, stopping in Edmonds and Everett. Intercity bus service is provided by
Greyhound Lines and
Northwestern Trailways from Everett Station.
Airports Snohomish County has one major airport:
Paine Field, otherwise known as Snohomish County Airport, which has had passenger service since March 2019. There are three smaller public airports that are open to
general aviation:
Arlington Municipal Airport in
Arlington,
Darrington Municipal Airport in
Darrington, and
Harvey Field in
Snohomish. The county also has several private airports, including the
Frontier Airpark and
Green Valley Airfield in Granite Falls. The
Martha Lake Airport in
Martha Lake was a former private airport that was closed in 2000 and was converted into a county
park that opened in 2010.
Ferries Snohomish County is also connected to adjacent counties by two ferry routes operated by
Washington State Ferries. The
Edmonds–Kingston ferry carries
SR 104 between
Edmonds and
Kingston in
Kitsap County. The
Mukilteo–Clinton ferry carries
SR 525 from Mukilteo to
Clinton on
Whidbey Island. ==Communities==