| Willoughby to Odenton (Maryland) | 305.52 mi (491.69 km) |
| Willoughby to Odessa (Texas) | 1,335.72 mi (2,149.64 km) |
| Willoughby to Ogden (Utah) | 1,574.86 mi (2,534.49 km) |
| Willoughby to Oildale (California) | 2,061.08 mi (3,316.99 km) |
| Willoughby to Ojus (Florida) | 1,086.38 mi (1,748.35 km) |
| Willoughby to Okemos (Michigan) | 170.39 mi (274.22 km) |
| Willoughby to Oklahoma City (Oklahoma) | 967.13 mi (1,556.45 km) |
| Willoughby to Okmulgee (Oklahoma) | 889.73 mi (1,431.88 km) |
| Willoughby to Olathe (Kansas) | 731.55 mi (1,177.31 km) |
| Willoughby to Old Jamestown (Missouri) | 506.39 mi (814.96 km) |
| Willoughby to Oldsmar (Florida) | 942.03 mi (1,516.05 km) |
| Willoughby to Olean (New York) | 156.07 mi (251.18 km) |
| Willoughby to Olive Branch (Mississippi) | 649.50 mi (1,045.27 km) |
| Willoughby to Olivehurst (California) | 2,101.97 mi (3,382.79 km) |
| Willoughby to Olney (Maryland) | 286.12 mi (460.47 km) |
