Warrenton is a city in Clatsop County, Oregon, United States. The city is named for D.K. (Daniel Knight) Warren, an early settler. The population was 4,096 at the 2000 census.
The first settlement within the Warrenton city limits was Lexington, which was laid out in 1848, and served as the first county seat for Clatsop county. The name fell out of use, and this area became known as Skipanon, which is preserved in the name of Skipanon River which flows through the town. A Lexington post office operated intermittently between 1850 and 1857; a Skipanon post office operated without a break from 1871 to 1903.
Fort Stevens was built in the Warrenton area in 1863. Its remains are preserved as part of Lewis and Clark National and State Historical Parks.