List of highways numbered 66

International

• European route E66

Australia

• Barkly Highway
• Riddoch Highway

Canada

• Alberta Highway 66
• Highway 66 (Ontario)

Cuba

• Autopista Sancti Spiritus

Finland

• Kantatie 66

France

• A66 autoroute

Germany

• Bundesautobahn 66

Greece

• Greek National Road 66, a national highway connecting Nemea with Levidi via Skoteini

Hungary

• 66-os főút (Kaposvár – Pécs)

India

• National Highway 66 (India)

Ireland

• N66

Israel

• Highway 66 (Israel)

Malaysia

• Malaysia Federal Route 66

Philippines

• N66 highway (Philippines)

Slovakia

• Road 66 (Slovakia), from Slovak – Hungarian border at Šahy to Tatras mountain

Spain

• Autovía A-66

United Arab Emirates

• E 66

United Kingdom

• A66 road
• M66 motorway

United States

• Interstate 66, a highway connecting Interstate 81 in Virginia, to Washington, DC
• * Interstate 66 (Kansas–Kentucky), a former proposed highway to connect Kansas with Kentucky
• U.S. Route 66, the most common meaning. Since 1985, when US 66 was decommissioned, several states where US 66 passed have re-commissioned part of the former route in that state as a state route 66. In the list of state routes 66 below, those marked with an asterisk have a connection with the former US 66.
• Alabama State Route 66
• Arizona State Route 66*
• Arkansas Highway 66
• California State Route 66*
• * County Route 66 (San Bernardino County, California)*
• Colorado State Highway 66
• Connecticut Route 66
• Florida State Road 66
• Georgia State Route 66
• Hawaii Route 66
• Idaho State Highway 66
• Illinois Route 66
• Indiana State Road 66
• Iowa Highway 66
• K-66 (Kansas highway)*
• Kentucky Route 66
• Louisiana Highway 66
• Maryland Route 66
• Massachusetts Route 66
• M-66 (Michigan highway)
• Minnesota State Highway 66
• * County Road 66 (Hennepin County, Minnesota)
• Missouri Route 66*
• * Missouri Route 66 (1922)
• Montana Highway 66
• Nebraska Highway 66
• * Nebraska Spur 66A
• * Nebraska Spur 66C
• * Nebraska Spur 66D
• * Nebraska Spur 66E
• Nevada State Route 66
• New Jersey Route 66
• New York State Route 66
• *County Route 66A (Cayuga County, New York)
• **County Route 66B (Cayuga County, New York)
• * County Route 66 (Chautauqua County, New York)
• * County Route 66 (Dutchess County, New York)
• * County Route 66 (Jefferson County, New York)
• * County Route 66 (Monroe County, New York)
• * County Route 66 (Onondaga County, New York)
• * County Route 66 (Putnam County, New York)
• * County Route 66 (Rensselaer County, New York)
• * County Route 66 (Saratoga County, New York)
• * County Route 66 (Schoharie County, New York)
• * County Route 66 (Suffolk County, New York)
• * County Route 66 (Sullivan County, New York)
• *County Route 66A (Westchester County, New York)
• North Carolina Highway 66
• North Dakota Highway 66
• Ohio State Route 66
• Oklahoma State Highway 66*
• * Oklahoma State Highway 66B*
• Oregon Route 66
• Pennsylvania Route 66
• Puerto Rico Highway 66
• South Carolina Highway 66
• Tennessee State Route 66
• Texas State Highway 66
• * Texas State Highway Loop 66
• * Texas State Highway Spur 66
• * Farm to Market Road 66
• * Texas Park Road 66
• U.S. Virgin Islands Highway 66
• Utah State Route 66
• Vermont Route 66
• Virginia State Route 66
• West Virginia Route 66
• Wisconsin Highway 66