List of highways numbered 81
Route 81 or Highway 81 may refer to:
International
- Asian Highway 81
- European route E81
Australia
- Escort Way
- Mulligan Highway and Peninsula Developmental Road – Queensland State Route 81
Canada
- Newfoundland and Labrador Route 81
Greece
- EO81 road
India
- National Highway 81
Korea, South
- National Route 81
Mexico
- Mexican Federal Highway 81
Philippines
- N81 highway
United States
- Interstate 81
- * Interstate 81E
- * Interstate 81S
- U.S. Route 81
- Alabama State Route 81
- * County Route 81
- Arizona State Route 81
- Arkansas Highway 81
- California State Route 81
- Connecticut Route 81
- Florida State Road 81
- * County Road 81A
- Georgia State Route 81
- Idaho State Highway 81
- Illinois Route 81
- Iowa Highway 81
- Kentucky Route 81
- Louisiana Highway 81
- * Louisiana State Route 81
- Maryland Route 81
- Massachusetts Route 81
- M-81
- Minnesota:
- * Minnesota State Highway 81
- * Minnesota State Highway 81
- Missouri Route 81
- Montana Highway 81
- Nebraska Highway 81
- Nevada State Route 81
- New Jersey Route 81
- * County Route 81
- New Mexico State Road 81
- New York State Route 81
- * County Route 81A
- **County Route 81C
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- * County Route 81
- North Carolina Highway 81
- Country Road 81
- Ohio State Route 81
- Oklahoma State Highway 81A
- Pennsylvania Route 81
- Rhode Island Route 81
- South Carolina Highway 81
- South Dakota Highway 81
- Tennessee State Route 81
- *Tennessee State Route 81A
- Texas State Highway 81
- * Texas State Highway Loop 81
- * Farm to Market Road 81
- Utah State Route 81
- Virginia State Route 81
- West Virginia Route 81
- * West Virginia Route 81
- Wisconsin Highway 81
- U.S. Virgin Islands Highway 81