| San Marcos to Indianapolis (Indiana) | 1,774.56 mi (2,855.88 km) |
| San Marcos to Indianola (Iowa) | 1,411.55 mi (2,271.67 km) |
| San Marcos to Indio (California) | 68.21 mi (109.77 km) |
| San Marcos to Inglewood (California) | 88.10 mi (141.79 km) |
| San Marcos to Inkster (Michigan) | 1,940.89 mi (3,123.56 km) |
| San Marcos to Inver Grove Heights (Minnesota) | 1,517.48 mi (2,442.16 km) |
| San Marcos to Inwood (New York) | 2,429.60 mi (3,910.06 km) |
| San Marcos to Iona (Florida) | 2,149.21 mi (3,458.81 km) |
| San Marcos to Ionia (Michigan) | 1,860.23 mi (2,993.76 km) |
| San Marcos to Iowa City (Iowa) | 1,518.45 mi (2,443.71 km) |
| San Marcos to Irmo (South Carolina) | 2,060.43 mi (3,315.94 km) |
| San Marcos to Irondale (Alabama) | 1,755.14 mi (2,824.63 km) |
| San Marcos to Ironton (Ohio) | 1,956.12 mi (3,148.08 km) |
| San Marcos to Irvine (California) | 50.98 mi (82.05 km) |
| San Marcos to Irving (Texas) | 1,169.14 mi (1,881.55 km) |
