| Middlesex to Johnstown (Pennsylvania) | 232.91 mi (374.84 km) |
| Middlesex to Joliet (Illinois) | 713.45 mi (1,148.19 km) |
| Middlesex to Jonesboro (Arkansas) | 936.11 mi (1,506.52 km) |
| Middlesex to Joplin (Missouri) | 1,100.81 mi (1,771.59 km) |
| Middlesex to Joppatowne (Maryland) | 126.39 mi (203.41 km) |
| Middlesex to Juana Díaz (Puerto Rico) | 1,627.11 mi (2,618.58 km) |
| Middlesex to Junction City (Kansas) | 1,187.97 mi (1,911.86 km) |
| Middlesex to Juneau (Alaska) | 2,831.25 mi (4,556.45 km) |
| Middlesex to Jupiter (Florida) | 996.40 mi (1,603.55 km) |
| Middlesex to Jupiter Farms (Florida) | 998.22 mi (1,606.48 km) |
| Middlesex to Jurupa Valley (California) | 2,381.19 mi (3,832.15 km) |
| Middlesex to Justice (Illinois) | 697.59 mi (1,122.65 km) |
| Middlesex to Kahului (Hawaii) | 4,882.83 mi (7,858.16 km) |
| Middlesex to Kailua (Hawaii) | 4,926.78 mi (7,928.88 km) |
| Middlesex to Kalamazoo (Michigan) | 585.84 mi (942.82 km) |
