| Walnut Creek to Oskaloosa (Iowa) | 1,574.95 mi (2,534.63 km) |
| Walnut Creek to Oswego (Illinois) | 1,796.56 mi (2,891.28 km) |
| Walnut Creek to Oswego (New York) | 2,386.65 mi (3,840.94 km) |
| Walnut Creek to Otsego (Minnesota) | 1,544.80 mi (2,486.11 km) |
| Walnut Creek to Ottawa (Illinois) | 1,772.53 mi (2,852.61 km) |
| Walnut Creek to Ottawa (Kansas) | 1,448.51 mi (2,331.15 km) |
| Walnut Creek to Ottumwa (Iowa) | 1,586.99 mi (2,554.02 km) |
| Walnut Creek to Overland (Missouri) | 1,709.60 mi (2,751.33 km) |
| Walnut Creek to Overland Park (Kansas) | 1,477.23 mi (2,377.37 km) |
| Walnut Creek to Overlea (Maryland) | 2,432.77 mi (3,915.16 km) |
| Walnut Creek to Oviedo (Florida) | 2,423.87 mi (3,900.84 km) |
| Walnut Creek to Owasso (Oklahoma) | 1,443.95 mi (2,323.81 km) |
| Walnut Creek to Owatonna (Minnesota) | 1,553.04 mi (2,499.38 km) |
| Walnut Creek to Owensboro (Kentucky) | 1,894.50 mi (3,048.90 km) |
| Walnut Creek to Owings Mills (Maryland) | 2,417.78 mi (3,891.05 km) |
