| Round Rock to Jeffersontown (Kentucky) | 868.86 mi (1,398.29 km) |
| Round Rock to Jeffersonville (Indiana) | 868.11 mi (1,397.10 km) |
| Round Rock to Jenison (Michigan) | 1,075.35 mi (1,730.62 km) |
| Round Rock to Jenks (Oklahoma) | 390.41 mi (628.30 km) |
| Round Rock to Jennings (Missouri) | 704.90 mi (1,134.43 km) |
| Round Rock to Jensen Beach (Florida) | 1,076.91 mi (1,733.12 km) |
| Round Rock to Jericho (New York) | 1,521.42 mi (2,448.49 km) |
| Round Rock to Jerome (Idaho) | 1,253.68 mi (2,017.60 km) |
| Round Rock to Jersey City (New Jersey) | 1,493.90 mi (2,404.20 km) |
| Round Rock to Jessup (Maryland) | 1,321.47 mi (2,126.70 km) |
| Round Rock to Johns Creek (Georgia) | 822.07 mi (1,322.99 km) |
| Round Rock to Johnson City (New York) | 1,442.94 mi (2,322.18 km) |
| Round Rock to Johnson City (Tennessee) | 966.96 mi (1,556.17 km) |
| Round Rock to Johnston (Iowa) | 801.86 mi (1,290.47 km) |
| Round Rock to Johnstown (Colorado) | 792.24 mi (1,274.99 km) |
