| Boulder to Joliet (Illinois) | 899.34 mi (1,447.34 km) |
| Boulder to Jonesboro (Arkansas) | 844.49 mi (1,359.08 km) |
| Boulder to Joplin (Missouri) | 615.12 mi (989.94 km) |
| Boulder to Joppatowne (Maryland) | 1,529.71 mi (2,461.83 km) |
| Boulder to Juana Díaz (Puerto Rico) | 2,757.06 mi (4,437.06 km) |
| Boulder to Junction City (Kansas) | 452.85 mi (728.78 km) |
| Boulder to Juneau (Alaska) | 1,796.86 mi (2,891.76 km) |
| Boulder to Jupiter (Florida) | 1,699.28 mi (2,734.72 km) |
| Boulder to Jupiter Farms (Florida) | 1,694.07 mi (2,726.35 km) |
| Boulder to Jurupa Valley (California) | 791.12 mi (1,273.18 km) |
| Boulder to Justice (Illinois) | 915.98 mi (1,474.13 km) |
| Boulder to Kahului (Hawaii) | 3,272.23 mi (5,266.14 km) |
| Boulder to Kailua (Hawaii) | 3,318.48 mi (5,340.58 km) |
| Boulder to Kalamazoo (Michigan) | 1,032.43 mi (1,661.54 km) |
| Boulder to Kalispell (Montana) | 722.04 mi (1,162.01 km) |
