Annexation is the process by which an area becomes part of a city. Incorporation is the process of creating a new city. State law gives cities and residents of unincorporated areas control over annexation and incorporation decisions. Both processes can be initiated by either the city or residents.

• An overview of the  annexation process (90KB PDF)
• An overview of the incorporation process

The Boundary Review Board reviews proposals for boundary changes by cities, including city annexations and new city incorporations.

In the case of new city incorporations, the Boundary Review Board oversees preparation of an impartial consultant study to assess the financial feasibility of the proposed new city. Following completion of the study, the Board holds a public hearing, establishes final boundaries, and makes a recommendation to the voters, who make the final decision in an election on the incorporation.

For annexations, the Boundary Review Board notifies all potentially interested jurisdictions of the action, but holds a hearing only if the action is contested. The request for a hearing and Board review must come from an affected jurisdiction or from residents or property owners by petition. Following the hearing in contested cases, the Board may approve, deny, or modify the boundaries of the proposed annexation, merger or other boundary action.

Additional information

• Washington St. Boundary Review Board for King County
• Countywide Planning Policies
• King County's Comprehensive Plan
• Puget Sound Regional Council (external link)
• Municipal Research and Services Center of Washington (external link)
• Washington State Growth Management Program (external link)