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To learn about Sound Transit's current and planned projects explore the new System Expansion interactive map. This website is no longer being updated.

The Sound Transit 3 measure will be decided by voters within the Sound Transit District, or more formally the Central Puget Sound Regional Transit Authority (RTA) District. This is the area where RTA taxes are collected and where the services they support are provided. The district includes the most populated areas of King, Pierce and Snohomish counties. Use the address locator tool to find out if your home address is within the district boundary.