The following highways are numbered 304:

Brazil

• BR-304

Canada

• Manitoba Provincial Road 304
• Nova Scotia Route 304
• Prince Edward Island Route 304
• Saskatchewan Highway 304

China

• China National Highway 304

Costa Rica

• National Route 304

Hungary

• Main road 304 (Hungary)

Japan

• Japan National Route 304

Thailand

• Highway 304 (Thailand)

United States

• Arkansas Highway 304
  • Arkansas Highway 304N
• Florida State Road 304 (former)
• Georgia State Route 304 (former)
• Louisiana Highway 304
• Maryland Route 304
• Mississippi Highway 304
• Montana Secondary Highway 304
• Nevada State Route 304
• New Mexico State Road 304
• New York State Route 304
• North Carolina Highway 304
• Ohio State Route 304
• Pennsylvania Route 304
  • 
    Pennsylvania Route 304 Truck
• South Carolina Highway 304
• Tennessee State Route 304
• Texas:
  • Texas State Highway 304
  • Texas State Highway Loop 304
  • Farm to Market Road 304
• Utah State Route 304
• Virginia State Route 304
• Washington State Route 304

Other areas:

• Puerto Rico Highway 304
• U.S. Virgin Islands Highway 304