Ilwaco is a city in Pacific County, Washington, United States. The city is located on the southern edge of the Long Beach Peninsula, on the north bank of the Columbia River where it meets the Pacific Ocean. It is near the city of Astoria, Oregon, which lies to the southeast on the southern bank of the Columbia. The population was 936 at the 2010 census. Founded in 1890, the city was home to the Ilwaco Railway and Navigation Company along the Long Beach Peninsula, with its core economy based on logging and timber rafting. The train ran out on the dock in Ilwaco. Floating logs were stored behind log booms on the west side of the Ilwaco dock. At some point after 1890, First Street had been covered with wooden planks and remained so until 1916, when it was paved over.

In addition to the city's logging industry, it has had a history as a cranberry producer, with cranberry bogs located immediately north of its downtown. It is currently an active fishing port.