| Middlesex to Odessa (Texas) | 1,655.41 mi (2,664.13 km) |
| Middlesex to Ogden (Utah) | 1,941.87 mi (3,125.14 km) |
| Middlesex to Oildale (California) | 2,424.32 mi (3,901.57 km) |
| Middlesex to Ojus (Florida) | 1,060.98 mi (1,707.47 km) |
| Middlesex to Okemos (Michigan) | 532.23 mi (856.54 km) |
| Middlesex to Oklahoma City (Oklahoma) | 1,297.10 mi (2,087.47 km) |
| Middlesex to Okmulgee (Oklahoma) | 1,215.08 mi (1,955.48 km) |
| Middlesex to Olathe (Kansas) | 1,083.58 mi (1,743.85 km) |
| Middlesex to Old Jamestown (Missouri) | 846.33 mi (1,362.03 km) |
| Middlesex to Oldsmar (Florida) | 981.78 mi (1,580.02 km) |
| Middlesex to Olean (New York) | 228.98 mi (368.51 km) |
| Middlesex to Olive Branch (Mississippi) | 921.84 mi (1,483.55 km) |
| Middlesex to Olivehurst (California) | 2,468.96 mi (3,973.41 km) |
| Middlesex to Olney (Maryland) | 168.27 mi (270.80 km) |
| Middlesex to Olympia (Washington) | 2,414.38 mi (3,885.57 km) |
