| Rancho Santa Margarita to Olympia (Washington) | 967.03 mi (1,556.28 km) |
| Rancho Santa Margarita to Olympia Heights (Florida) | 2,289.35 mi (3,684.35 km) |
| Rancho Santa Margarita to Omaha (Nebraska) | 1,289.57 mi (2,075.36 km) |
| Rancho Santa Margarita to On Top of the World Designated Place (Florida) | 2,096.34 mi (3,373.73 km) |
| Rancho Santa Margarita to Onalaska (Wisconsin) | 1,579.22 mi (2,541.50 km) |
| Rancho Santa Margarita to Oneida (New York) | 2,337.51 mi (3,761.86 km) |
| Rancho Santa Margarita to Oneonta (New York) | 2,366.79 mi (3,808.99 km) |
| Rancho Santa Margarita to Ontario (California) | 28.16 mi (45.32 km) |
| Rancho Santa Margarita to Ontario (Oregon) | 718.94 mi (1,157.02 km) |
| Rancho Santa Margarita to Opa-locka (Florida) | 2,289.49 mi (3,684.57 km) |
| Rancho Santa Margarita to Opelika (Alabama) | 1,857.70 mi (2,989.68 km) |
| Rancho Santa Margarita to Opelousas (Louisiana) | 1,505.34 mi (2,422.60 km) |
| Rancho Santa Margarita to Orange (California) | 17.48 mi (28.13 km) |
| Rancho Santa Margarita to Orange (Texas) | 1,416.24 mi (2,279.21 km) |
| Rancho Santa Margarita to Orange City (Florida) | 2,157.39 mi (3,471.98 km) |
