Claremore is a city and the county seat of Rogers County in Green Country or northeastern Oklahoma, United States. The population was 19,580 at the 2020 census, a 5.4 percent increase over the figure of 18,581 recorded in 2010. Located in the foothills of the Ozark Mountains. It is home of Rogers State University. This area was part of the territory of the Osage, but they were forced out under a treaty with the United States.