The following highways are numbered 503:
Canada edit
Costa Rica edit
India edit
Japan edit
United States edit
- County Road 503 (Brevard County, Florida)
- Maryland Route 503 (former)
- County Route 503 (New Jersey)
- Ohio State Route 503
- Washington State Route 503
- Territories
Preceded by 502 |
Lists of highways 503 |
Succeeded by 504 |