The following highways are numbered 172:

Canada

• New Brunswick Route 172
• Prince Edward Island Route 172
• Quebec Route 172

Ireland

• R172 road

Japan

• Japan National Route 172

United States

• Interstate 172 (former)
• Interstate 172
• Alabama State Route 172
• Arizona State Route 172 (former)
• California State Route 172
• Colorado State Highway 172
• Connecticut Route 172
• Georgia State Route 172
• Illinois Route 172
• Kentucky Route 172
• Louisiana Highway 172
• Maine State Route 172
• Maryland Route 172
• M-172 (Michigan highway) (former)
• Minnesota State Highway 172
• Mississippi Highway 172
• Missouri Route 172
• Nevada State Route 172
• New Jersey Route 172
• New Mexico State Road 172
• New York State Route 172
• North Carolina Highway 172
• Ohio State Route 172
• Pennsylvania Route 172 (former)
• South Carolina Highway 172
• Tennessee State Route 172
• Texas State Highway 172
  • Texas State Highway Loop 172
  • Texas State Highway Spur 172
  • Farm to Market Road 172 (Texas)
• Utah State Route 172
• Virginia State Route 172
• Washington State Route 172
• Wisconsin Highway 172
• Wyoming Highway 172

Territories:

• Puerto Rico Highway 172