Fairborn is a city in Greene County, Ohio, United States. The population was 34,620 at the 2020 census. It is a suburb of Dayton and part of the Dayton metropolitan area. The city is home to Wright State University, which serves nearly 12,000 undergraduate and graduate students. The city also hosts the disaster training facility known informally as Calamityville.

Greene County is located in the southwestern portion of Ohio. As of the 2020 census, the population was 167,966. Its county seat is Xenia and its largest city is Beavercreek. The county was established on March 24, 1803 and named for General Nathanael Greene, an officer in the Revolutionary War. Greene County is part of the Dayton, OH Metropolitan Statistical Area.