Route 405 or Highway 405 may refer to:

Canada[edit]

• Manitoba Provincial Road 405
• Newfoundland and Labrador Route 405
• Ontario Highway 405

Costa Rica[edit]

• National Route 405

Japan[edit]

• Japan National Route 405

United Kingdom[edit]

• A405 road

United States[edit]

• Interstate 405
  • Interstate 405 (California), a bypass of Los Angeles, California
  • Interstate 405 (Oregon), a bypass of Portland, Oregon
  • Interstate 405 (Washington), a bypass of Seattle, Washington
• Florida:
  • Florida State Road 405
  • County Road 405 (Brevard County, Florida)
• Georgia State Route 405 (unsigned designation for Interstate 95)
• Maryland Route 405
• New York:
  • New York State Route 405 (former)
  • County Route 405 (Albany County, New York)
  • County Route 405 (Erie County, New York)
• Pennsylvania Route 405
• Puerto Rico Highway 405
• Virginia State Route 405