According to the United States Census Bureau, the city has a total area of , of which, is land and is water. The city is located between the Willamette and Tualatin rivers; it includes the former townsites/developments of Willamette, Bolton, Multnomah City, Sunset City, and West Oregon City. Willamette was incorporated in 1908, the City of West Linn was incorporated in 1913, and the two towns merged in 1916. Later annexations brought in the Cedaroak, Marylhurst and Hidden Springs neighborhoods. Infill created the Tanner Basin and Tannler neighborhoods.