| San Marcos to Ukiah (California) | 534.46 mi (860.13 km) |
| San Marcos to Union (Missouri) | 1,506.91 mi (2,425.14 km) |
| San Marcos to Union City (California) | 411.92 mi (662.92 km) |
| San Marcos to Union City (Georgia) | 1,874.28 mi (3,016.36 km) |
| San Marcos to Union City (New Jersey) | 2,414.55 mi (3,885.85 km) |
| San Marcos to Union City (Tennessee) | 1,606.52 mi (2,585.44 km) |
| San Marcos to Union Hill-Novelty Hill (Washington) | 1,036.28 mi (1,667.73 km) |
| San Marcos to Union Park (Florida) | 2,144.52 mi (3,451.28 km) |
| San Marcos to Uniondale (New York) | 2,437.55 mi (3,922.86 km) |
| San Marcos to Universal City (Texas) | 1,138.81 mi (1,832.74 km) |
| San Marcos to University (Florida) | 2,085.63 mi (3,356.50 km) |
| San Marcos to University City (Missouri) | 1,544.08 mi (2,484.95 km) |
| San Marcos to University Heights (Ohio) | 2,025.82 mi (3,260.24 km) |
| San Marcos to University of California-Santa Barbara (California) | 177.63 mi (285.88 km) |
| San Marcos to University Park (Texas) | 1,179.38 mi (1,898.03 km) |
