Mason City
- Country: United States
- State: Iowa
- Population: 27,430 (2016)
- Latitude: 43° 9.2' N (43.15357°)
- Longitude: 93° 12.1' W (-93.20104°)
- Elevation: 344 m/1,130 ft. above sea level
- Time zone: America/Chicago (UTC -06:00); DST observed (UTC -05:00)