Tualatin (pronounce /tuːˈɔːlətɨn/) is a city is located primarily in Washington County in the U.S. state of Oregon. A small portion of the city is also located in neighboring Clackamas County. It is a southwestern suburb in the Portland Metropolitan Area that is located south of Tigard. The population was 22,791 at the 2000 census. The 2006 estimate is 25,650 residents.