The following highways are numbered 306:

Canada

• Nova Scotia Route 306
• Prince Edward Island Route 306
• Saskatchewan Highway 306

China

• China National Highway 306

Costa Rica

• National Route 306

Hungary

• Main road 306 (Hungary)

India

• National Highway 306 (India)

Japan

• Japan National Route 306

Philippines

• N306 highway (Philippines)

United States

• Arkansas Highway 306
• Florida State Road 306 (former)
• Georgia State Route 306
• Iowa Highway 306 (former)
• Kentucky Route 306
• Louisiana Highway 306
• Maryland Route 306
• Mississippi Highway 306
• Montana Secondary Highway 306
• Nevada State Route 306
• New York:
  • New York State Route 306
  • County Route 306 (Albany County, New York)
  • County Route 306 (Erie County, New York)
• North Carolina Highway 306
• Ohio State Route 306
• Tennessee State Route 306
• Texas State Highway 306 (former)
  • Texas State Highway Loop 306
  • Farm to Market Road 306
• Utah State Route 306
• Virginia State Route 306
• Washington State Route 306 (former)

Other areas:

• Puerto Rico Highway 306
• U.S. Virgin Islands Highway 306