| Giessen to Oestrich-Winkel | 49.90 mi (80.31 km) |
| Giessen to Offenburg | 149.89 mi (241.23 km) |
| Giessen to Oftersheim | 83.87 mi (134.97 km) |
| Giessen to Ohrdruf | 91.97 mi (148.01 km) |
| Giessen to Ohringen | 102.52 mi (164.99 km) |
| Giessen to Olbernhau | 204.60 mi (329.26 km) |
| Giessen to Olching | 203.24 mi (327.09 km) |
| Giessen to Oldenburg | 177.97 mi (286.42 km) |
| Giessen to Oldenburg in Holstein | 273.21 mi (439.68 km) |
| Giessen to Olfen | 96.05 mi (154.58 km) |
| Giessen to Olpe | 47.13 mi (75.85 km) |
| Giessen to Olsberg | 53.57 mi (86.22 km) |
| Giessen to Oranienburg | 246.61 mi (396.88 km) |
| Giessen to Ortenberg | 23.22 mi (37.37 km) |
| Giessen to Oschatz | 199.53 mi (321.12 km) |
