| Hackettstown to Olympia Heights (Florida) | 1,092.17 mi (1,757.67 km) |
| Hackettstown to Omaha (Nebraska) | 1,103.53 mi (1,775.95 km) |
| Hackettstown to On Top of the World Designated Place (Florida) | 914.15 mi (1,471.18 km) |
| Hackettstown to Onalaska (Wisconsin) | 860.51 mi (1,384.86 km) |
| Hackettstown to Oneida (New York) | 159.48 mi (256.66 km) |
| Hackettstown to Oneonta (New York) | 111.32 mi (179.16 km) |
| Hackettstown to Ontario (California) | 2,369.28 mi (3,812.99 km) |
| Hackettstown to Ontario (Oregon) | 2,136.87 mi (3,438.96 km) |
| Hackettstown to Opa-locka (Florida) | 1,079.08 mi (1,736.61 km) |
| Hackettstown to Opelika (Alabama) | 812.20 mi (1,307.11 km) |
| Hackettstown to Opelousas (Louisiana) | 1,199.20 mi (1,929.93 km) |
| Hackettstown to Orange (California) | 2,387.25 mi (3,841.90 km) |
| Hackettstown to Orange (Texas) | 1,293.30 mi (2,081.36 km) |
| Hackettstown to Orange City (Florida) | 900.61 mi (1,449.39 km) |
| Hackettstown to Orangeburg (South Carolina) | 607.34 mi (977.41 km) |
