| National City to Odessa (Texas) | 862.90 mi (1,388.71 km) |
| National City to Ogden (Utah) | 655.61 mi (1,055.11 km) |
| National City to Oildale (California) | 220.68 mi (355.15 km) |
| National City to Ojus (Florida) | 2,261.40 mi (3,639.38 km) |
| National City to Okemos (Michigan) | 1,902.48 mi (3,061.74 km) |
| National City to Oklahoma City (Oklahoma) | 1,135.59 mi (1,827.55 km) |
| National City to Okmulgee (Oklahoma) | 1,220.79 mi (1,964.66 km) |
| National City to Olathe (Kansas) | 1,316.63 mi (2,118.92 km) |
| National City to Old Jamestown (Missouri) | 1,556.49 mi (2,504.93 km) |
| National City to Oldsmar (Florida) | 2,068.11 mi (3,328.29 km) |
| National City to Olean (New York) | 2,199.60 mi (3,539.92 km) |
| National City to Olive Branch (Mississippi) | 1,567.57 mi (2,522.77 km) |
| National City to Olivehurst (California) | 508.46 mi (818.28 km) |
| National City to Olney (Maryland) | 2,265.51 mi (3,645.98 km) |
| National City to Olympia (Washington) | 1,039.06 mi (1,672.21 km) |
