The following highways are numbered 406:

Canada

• Manitoba Provincial Road 406
• Newfoundland and Labrador Route 406
• Ontario Highway 406

Costa Rica

• National Route 406

Israel

• Route 406 (Israel)

Japan

• Japan National Route 406

United Kingdom

• North Circular Road, the top half of London's ring road from Chiswick in the West to the Woolwich Ferry in the East

United States

• Florida:
  • Florida State Road 406
    • Florida State Road 406A
  • County Road 406 (Brevard County, Florida)
• Georgia State Route 406 (unsigned designation for Interstate 59)
• Louisiana Highway 406
• Maryland Route 406 (former)
• New Mexico State Road 406
• New York:
  • New York State Route 406
  • County Route 406 (Erie County, New York)
• Puerto Rico Highway 406
• Virginia State Route 406
  • Virginia State Route 406 (former)