| Round Rock to Commerce (California) | 1,218.60 mi (1,961.15 km) |
| Round Rock to Commerce City (Colorado) | 761.25 mi (1,225.12 km) |
| Round Rock to Compton (California) | 1,222.22 mi (1,966.98 km) |
| Round Rock to Comstock Park (Michigan) | 1,087.47 mi (1,750.11 km) |
| Round Rock to Concord (California) | 1,476.75 mi (2,376.60 km) |
| Round Rock to Concord (Missouri) | 690.39 mi (1,111.07 km) |
| Round Rock to Concord (New Hampshire) | 1,678.04 mi (2,700.55 km) |
| Round Rock to Concord (North Carolina) | 1,041.15 mi (1,675.57 km) |
| Round Rock to Conneaut (Ohio) | 1,232.15 mi (1,982.95 km) |
| Round Rock to Connersville (Indiana) | 946.56 mi (1,523.35 km) |
| Round Rock to Conroe (Texas) | 130.74 mi (210.41 km) |
| Round Rock to Converse (Texas) | 80.20 mi (129.06 km) |
| Round Rock to Conway (Arkansas) | 435.50 mi (700.87 km) |
| Round Rock to Conway (Florida) | 991.12 mi (1,595.06 km) |
| Round Rock to Conway (South Carolina) | 1,111.04 mi (1,788.04 km) |
