Mill Creek is a city in Snohomish County, Washington, United States. It is located between the cities of Everett and Lynnwood, approximately 20 miles (32 km) northeast of Seattle. The city has a population of 18,244 as of the 2010 census population was 18,244. Mill Creek is one of the wealthiest suburbs in the Seattle metropolitan area and was originally built as a planned community.
The city lies along State Route 527 and North Creek, a tributary of the Sammamish River, and extends from Interstate 5 in the west to State Route 9 in the east. Mill Creek was a planned community conceived in the 1970s and built around a country club and golf course, with other development occurring nearby. It was incorporated as a city in 1983 and underwent major population growth due to continued suburban development and annexation of nearby areas. The city's downtown area is centered around the Mill Creek Town Center, a mixed-use lifestyle center and retail complex that opened in 2004.