| Pikesville to Olympia (Washington) | 2,349.47 mi (3,781.11 km) |
| Pikesville to Olympia Heights (Florida) | 967.40 mi (1,556.87 km) |
| Pikesville to Omaha (Nebraska) | 1,025.33 mi (1,650.10 km) |
| Pikesville to On Top of the World Designated Place (Florida) | 778.39 mi (1,252.70 km) |
| Pikesville to Onalaska (Wisconsin) | 809.54 mi (1,302.83 km) |
| Pikesville to Oneida (New York) | 260.45 mi (419.15 km) |
| Pikesville to Oneonta (New York) | 228.37 mi (367.53 km) |
| Pikesville to Ontario (California) | 2,275.84 mi (3,662.61 km) |
| Pikesville to Ontario (Oregon) | 2,080.86 mi (3,348.82 km) |
| Pikesville to Opa-locka (Florida) | 954.46 mi (1,536.05 km) |
| Pikesville to Opelika (Alabama) | 670.99 mi (1,079.86 km) |
| Pikesville to Opelousas (Louisiana) | 1,062.23 mi (1,709.50 km) |
| Pikesville to Orange (California) | 2,293.32 mi (3,690.74 km) |
| Pikesville to Orange (Texas) | 1,157.75 mi (1,863.22 km) |
| Pikesville to Orange City (Florida) | 768.15 mi (1,236.21 km) |
