Arlington is a city in northern Snohomish County, Washington, United States, part of the Seattle metropolitan area. The city lies on the Stillaguamish River in the western foothills of the Cascade Range, adjacent to the city of Marysville. It is approximately 10 miles (16 km) north of Everett, the county seat.
Arlington was established in the 1880s by settlers and the area was platted as two towns, Arlington and Haller City. Haller City was absorbed by the larger Arlington, which was incorporated as a city in 1903. During the Great Depression of the 1930s, the Arlington area was the site of major projects undertaken for employment under the direction of federal relief agencies, including construction of a municipal airport that would serve as a naval air station during World War II. Beginning in the 1980s, Arlington was affected by suburbanisation due to the expansion of Seattle and annexing the unincorporated area of Smokey Point to the south-west.
The economy of the Arlington area historically relied on timber and agriculture. In the early 21st century, it has transitioned to a service economy, with some aviation industry jobs near the municipal airport. The city is governed by a mayor–council government, electing a mayor and seven city council members. The municipal government maintains the city's parks system and water and wastewater utilities. Other services, including public utilities, public transportation, and schools, are contracted to regional or county-level agencies and companies.
Arlington has a population of over 19,800 people. Arlington also forms part of the wider Seattle-Tacoma-Bellevue metropolitan area which has a population of over 3,979,845 people.