Cleveland Hopkins International Airport is a city-owned international airport in Cleveland, Ohio, United States, and is the primary airport serving Greater Cleveland and Northeast Ohio. It is the largest and busiest airport in the state, as well as in the top fifty largest airports in the U.S. by passenger numbers. Located in Cleveland's Hopkins neighborhood 9 miles (14 km) southwest of Downtown Cleveland, it is adjacent to the Glenn Research Center, one of NASA's ten major field centers.