| Round Rock to Johnstown (Pennsylvania) | 1,249.78 mi (2,011.33 km) |
| Round Rock to Joliet (Illinois) | 925.73 mi (1,489.82 km) |
| Round Rock to Jonesboro (Arkansas) | 544.67 mi (876.56 km) |
| Round Rock to Joplin (Missouri) | 487.45 mi (784.48 km) |
| Round Rock to Joppatowne (Maryland) | 1,349.30 mi (2,171.49 km) |
| Round Rock to Juana Díaz (Puerto Rico) | 2,133.65 mi (3,433.77 km) |
| Round Rock to Junction City (Kansas) | 589.14 mi (948.14 km) |
| Round Rock to Juneau (Alaska) | 2,579.61 mi (4,151.48 km) |
| Round Rock to Jupiter (Florida) | 1,091.01 mi (1,755.81 km) |
| Round Rock to Jupiter Farms (Florida) | 1,084.72 mi (1,745.69 km) |
| Round Rock to Jurupa Valley (California) | 1,179.82 mi (1,898.74 km) |
| Round Rock to Justice (Illinois) | 948.33 mi (1,526.19 km) |
| Round Rock to Kahului (Hawaii) | 3,681.04 mi (5,924.05 km) |
| Round Rock to Kailua (Hawaii) | 3,742.80 mi (6,023.45 km) |
| Round Rock to Kalamazoo (Michigan) | 1,051.24 mi (1,691.81 km) |
