| Ontario to Romeoville (Illinois) | 1,683.80 mi (2,709.81 km) |
| Ontario to Romulus (Michigan) | 1,930.28 mi (3,106.48 km) |
| Ontario to Ronkonkoma (New York) | 2,458.27 mi (3,956.20 km) |
| Ontario to Roosevelt (New York) | 2,434.83 mi (3,918.48 km) |
| Ontario to Rosamond (California) | 66.82 mi (107.54 km) |
| Ontario to Rosaryville (Maryland) | 2,272.29 mi (3,656.89 km) |
| Ontario to Roscoe (Illinois) | 1,647.13 mi (2,650.81 km) |
| Ontario to Rose Hill (Virginia) | 2,257.04 mi (3,632.36 km) |
| Ontario to Roseburg (Oregon) | 705.82 mi (1,135.90 km) |
| Ontario to Rosedale (California) | 130.16 mi (209.47 km) |
| Ontario to Rosedale (Maryland) | 2,286.45 mi (3,679.68 km) |
| Ontario to Roselle (Illinois) | 1,688.19 mi (2,716.89 km) |
| Ontario to Roselle (New Jersey) | 2,399.56 mi (3,861.72 km) |
| Ontario to Roselle Park (New Jersey) | 2,399.16 mi (3,861.08 km) |
| Ontario to Rosemead (California) | 27.32 mi (43.97 km) |
