Bartlesville is a city mostly in Washington County in the U.S. state of Oklahoma. The population was 35,750 at the 2010 census, with a 2018 estimate of 36,423 according to the U.S. Census Bureau. Bartlesville is 47 mi north of Tulsa and 18 mi south of the Kansas border. It is the county seat of Washington County. The Caney River runs through Bartlesville.