Ryan Airfield (ICAO: KRYN, FAA LID: RYN), also known as Ryan Field, is a city owned, public use airport located 10 nautical miles (12 mi, 19 km) southwest of the central business district of Tucson, a city in Pima County, Arizona, United States. It is included in the National Plan of Integrated Airport Systems for 2011–2015, which categorized it as a reliever airport. It is mostly used for general aviation but also serves a significant amount of law enforcement and military helicopter activity.