A majority of the first phase 1,767 homes and condominiums were completed by early 1983, when an incorporation petition was submitted by residents after reaching the population threshold of 3,000 needed for cityhood. At the time, the homeowners association and county government had already provided much of the area's infrastructure and maintenance requirements, but local residents resisted attempts to raise property tax assessments. Mill Creek was officially incorporated as a city on September 30, 1983, ten days after a vote of residents passed, and encompassed . Mill Creek was the first new city to be incorporated in Snohomish County since Brier in 1965 and the newest in the state since Ocean Shores in 1970.