| San Mateo to Olympia (Washington) | 656.33 mi (1,056.27 km) |
| San Mateo to Olympia Heights (Florida) | 2,576.77 mi (4,146.91 km) |
| San Mateo to Omaha (Nebraska) | 1,419.45 mi (2,284.38 km) |
| San Mateo to On Top of the World Designated Place (Florida) | 2,364.28 mi (3,804.94 km) |
| San Mateo to Onalaska (Wisconsin) | 1,675.69 mi (2,696.76 km) |
| San Mateo to Oneida (New York) | 2,455.07 mi (3,951.06 km) |
| San Mateo to Oneonta (New York) | 2,490.87 mi (4,008.67 km) |
| San Mateo to Ontario (California) | 358.31 mi (576.65 km) |
| San Mateo to Ontario (Oregon) | 526.97 mi (848.07 km) |
| San Mateo to Opa-locka (Florida) | 2,575.48 mi (4,144.83 km) |
| San Mateo to Opelika (Alabama) | 2,101.21 mi (3,381.58 km) |
| San Mateo to Opelousas (Louisiana) | 1,788.99 mi (2,879.10 km) |
| San Mateo to Orange (California) | 361.28 mi (581.42 km) |
| San Mateo to Orange (Texas) | 1,709.41 mi (2,751.03 km) |
| San Mateo to Orange City (Florida) | 2,423.94 mi (3,900.95 km) |
