Ohio University (officially The Ohio University and often referred to and stylized as OHIO) is a public research university in Athens, Ohio. The first university chartered by an Act of Congress and the first to be chartered in Ohio, it was chartered in 1787 by the Congress of the Confederation and subsequently approved for the territory in 1802 and state in 1804, opening for students in 1809. Ohio University is the oldest university in Ohio, the tenth oldest public university in the United States and the 32nd oldest among public and private universities. As of fall 2020, the university's total enrollment at Athens was slightly more than 18,000, while the all-campus enrollment was just over 28,000.

Athens is a city and the county seat of Athens County, Ohio, United States. Athens is the home of Ohio University, a large public research university with an undergraduate and graduate enrollment of more than 21,000 students. Located along the Hocking River in the southeastern part of Ohio about 65 miles (105 km) southeast of Columbus, Athens is the principal city of the Athens, OH Micropolitan Statistical Area. The population of Athens as of the 2010 U.S. Census was 23,832.