| Johnston to Oswego (Illinois) | 277.87 mi (447.19 km) |
| Johnston to Oswego (New York) | 883.13 mi (1,421.26 km) |
| Johnston to Otsego (Minnesota) | 247.06 mi (397.61 km) |
| Johnston to Ottawa (Illinois) | 254.36 mi (409.35 km) |
| Johnston to Ottawa (Kansas) | 228.55 mi (367.82 km) |
| Johnston to Ottumwa (Iowa) | 82.05 mi (132.04 km) |
| Johnston to Overland (Missouri) | 272.26 mi (438.15 km) |
| Johnston to Overland Park (Kansas) | 200.28 mi (322.32 km) |
| Johnston to Overlea (Maryland) | 916.18 mi (1,474.46 km) |
| Johnston to Oviedo (Florida) | 1,142.85 mi (1,839.23 km) |
| Johnston to Owasso (Oklahoma) | 390.07 mi (627.76 km) |
| Johnston to Owatonna (Minnesota) | 167.70 mi (269.88 km) |
| Johnston to Owensboro (Kentucky) | 443.74 mi (714.13 km) |
| Johnston to Owings Mills (Maryland) | 901.22 mi (1,450.38 km) |
| Johnston to Owosso (Michigan) | 495.54 mi (797.50 km) |
