List of highways numbered 420

Route 420 or Highway 420 may refer to:

Australia

• Bass Highway (Victoria)

Canada

• Ontario Highway 420
• New Brunswick Route 420
• Newfoundland and Labrador Route 420

Ireland

• R420 road

Japan

• Japan National Route 420

Spain

• N-420

United States

• Interstate 420 (multiple highways)
• U.S. Route 420
• Florida:
  • Florida State Road 420 (former)
  • County Road 420 (Orange County, Florida)
• Louisiana Highway 420
• New York State Route 420
• Ohio State Route 420
• Pennsylvania Route 420
• South Carolina Highway 420
• Tennessee State Route 420
• Farm to Market Road 420
• Virginia State Route 420
• Kentucky State Route 420