| Green River to Olympia Heights (Florida) | 1,984.72 mi (3,194.11 km) |
| Green River to Omaha (Nebraska) | 695.08 mi (1,118.62 km) |
| Green River to On Top of the World Designated Place (Florida) | 1,745.32 mi (2,808.82 km) |
| Green River to Onalaska (Wisconsin) | 939.76 mi (1,512.41 km) |
| Green River to Oneida (New York) | 1,719.56 mi (2,767.36 km) |
| Green River to Oneonta (New York) | 1,756.03 mi (2,826.06 km) |
| Green River to Ontario (California) | 680.53 mi (1,095.20 km) |
| Green River to Ontario (Oregon) | 418.18 mi (673.00 km) |
| Green River to Opa-locka (Florida) | 1,980.80 mi (3,187.78 km) |
| Green River to Opelika (Alabama) | 1,455.52 mi (2,342.43 km) |
| Green River to Opelousas (Louisiana) | 1,229.10 mi (1,978.04 km) |
| Green River to Orange (California) | 700.95 mi (1,128.07 km) |
| Green River to Orange (Texas) | 1,177.22 mi (1,894.56 km) |
| Green River to Orange City (Florida) | 1,800.82 mi (2,898.14 km) |
| Green River to Orangeburg (South Carolina) | 1,653.78 mi (2,661.50 km) |
