| Ontario to Oak Grove (South Carolina) | 2,076.91 mi (3,342.47 km) |
| Ontario to Oak Harbor (Washington) | 1,018.60 mi (1,639.27 km) |
| Ontario to Oak Hills (Oregon) | 841.37 mi (1,354.05 km) |
| Ontario to Oak Lawn (Illinois) | 1,702.34 mi (2,739.64 km) |
| Ontario to Oak Park (California) | 67.15 mi (108.06 km) |
| Ontario to Oak Park (Illinois) | 1,702.22 mi (2,739.46 km) |
| Ontario to Oak Park (Michigan) | 1,941.28 mi (3,124.19 km) |
| Ontario to Oak Ridge (Florida) | 2,160.41 mi (3,476.85 km) |
| Ontario to Oak Ridge (New Jersey) | 2,385.86 mi (3,839.67 km) |
| Ontario to Oak Ridge (Tennessee) | 1,880.95 mi (3,027.09 km) |
| Ontario to Oakdale (California) | 314.66 mi (506.39 km) |
| Ontario to Oakdale (Minnesota) | 1,506.89 mi (2,425.10 km) |
| Ontario to Oakland (California) | 365.58 mi (588.35 km) |
| Ontario to Oakland (New Jersey) | 2,399.21 mi (3,861.15 km) |
| Ontario to Oakland Park (Florida) | 2,290.06 mi (3,685.50 km) |
