Stillwater is a city in north-central Oklahoma at the intersection of US-177 and State Highway 51. It is the county seat of Payne County, Oklahoma, United States. As of the 2010 census, the city population was 45,688, making it the tenth-largest city in Oklahoma. Stillwater is the principal city of the Stillwater Micropolitan Statistical Area which had a population of 78,399 according to the 2012 census estimate. Stillwater was part of the first Oklahoma Land Run held on April 22, 1889 when the Unassigned Lands were opened for settlement and became the core of the new Oklahoma Territory. The city charter was adopted on August 24, 1889. Stillwater is home to the main campus of Oklahoma State University as well as Northern Oklahoma College – Stillwater, Meridian Technology Center, and the Oklahoma Department of Career and Technology Education.