The following highways are numbered 315:

Canada

• Manitoba Provincial Road 315
• New Brunswick Route 315
• Prince Edward Island Route 315
• Quebec Route 315

China

• China National Highway 315

Costa Rica

• National Route 315

India

• National Highway 315 (India)

Japan

• Japan National Route 315

United States

• Interstate 315 (unsigned)
• Arkansas Highway 315
• Connecticut Route 315
• Florida State Road 315 (former)
• Georgia State Route 315
• Iowa Highway 315 (former)
• Kentucky Route 315
• Louisiana Highway 315
• Maryland Route 315
  • Maryland Route 315 (former)
• Mississippi Highway 315
• Montana Secondary Highway 315
• New Mexico State Road 315
• New York:
  • New York State Route 315
  • County Route 315 (Erie County, New York)
• Ohio State Route 315
  • Ohio State Route 315C (unsigned)
• Pennsylvania Route 315
• South Carolina Highway 315
• Tennessee State Route 315
• Texas:
  • Texas State Highway 315
  • Farm to Market Road 315
• Utah State Route 315
• Vermont Route 315
• Virginia State Route 315
• Wyoming Highway 315

Other areas:

• Puerto Rico Highway 315
• U.S. Virgin Islands Highway 315