The following highways are numbered 309:

Canada

• Manitoba Provincial Road 309
• Nova Scotia Route 309
• Prince Edward Island Route 309
• Quebec Route 309
• Saskatchewan Highway 309

China

• China National Highway 309

Costa Rica

• National Route 309

India

• National Highway 309 (India)

Japan

• Japan National Route 309

United States

• U.S. Route 309 (former)
• Arkansas Highway 309
• Connecticut Route 309
• Florida State Road 309 (former)
• Georgia State Route 309
• Kentucky Route 309
• Louisiana Highway 309
• Maryland Route 309
• Minnesota State Highway 309
• Mississippi Highway 309
• New Mexico State Road 309
• New York:
  • New York State Route 309
  • County Route 309 (Erie County, New York)
  • County Route 309 (Westchester County, New York)
• Ohio State Route 309
  • Ohio State Route 309 (former)
• Pennsylvania Route 309
  • 
    Pennsylvania Route 309 Business
• Puerto Rico Highway 309
• South Carolina Highway 309 (former)
• Tennessee State Route 309
• Texas:
  • Texas State Highway 309
  • Texas State Highway Spur 309
  • Farm to Market Road 309
• Utah State Route 309
• Virginia State Route 309