The 553-acre (224 ha) Thomas Lake area in the northeastern corner of the city, bordered to the north by 132nd Street and east by Seattle Hill Road, was annexed in 2005 and added 2,200 residents to the city’s population.
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 20,926 as of the 2020 census. The city lies along State Route 527 and North Creek, a tributary of the Sammamish River, on the east side of Interstate 5.