Bartlesville is a city mostly in Washington County in the U.S. state of Oklahoma. The population was 37,290 at the 2020 census. Bartlesville is 47 miles north of Tulsa and 18 miles south of the Kansas border. It is the county seat of Washington County. The Caney River runs through Bartlesville. Bartlesville is the primary city of the Bartlesville Micropolitan area, which consists of Washington County and had a population of 51,843 in 2018. A small portion of the city is in Osage County.