List of highways numbered 21

For roads named A21 see ; List of A21 roads
Route 21, or Highway 21, can refer to:

International[]

E21 European route E21

Australia[]

Austria[]

Wiener Außenring Autobahn

Cambodia[]

National Road 21 (Cambodia)

Canada[]

Costa Rica[]

National Route 21

Czech Republic[]

Highway; Czech: Silnice I/21

Hungary[]

Main road 21 (Hungary)

India[]

National Highway 21 (India)

Iran[]

Road 21

Japan[]

Japan National Route 21

Korea, South[]

National Route 21

Moldova[]

M21 highway (Moldova)

New Zealand[]

New Zealand State Highway 21

Paraguay[]

Turkey[]

O-21, a motorway in Turkey running from Kemerhisar, Niğde Province to Tarsus, Mersin Province.

United Kingdom[]

British A21 (Hastings-London)

United States[]

U.S. Route 21
Alabama State Route 21
Arkansas Highway 21
- Arkansas Highway 21E (former)
- Arkansas Highway 21W (former)
California State Route 21 (former)
- County Route A21 (California)
- County Route E21 (California)
- County Route G21 (California)
- County Route J21 (California)
- County Route S21 (California)
Colorado State Highway 21
Connecticut Route 21
Florida State Road 21
- County Road 21B (Clay County, Florida)
- County Road 21B (Duval County, Florida)
- County Road 21D (Duval County, Florida)
- County Road 21 (Marion County, Florida)
- County Road 21 (Putnam County, Florida)
Georgia State Route 21
Hawaii Route 21 (former)
Idaho State Highway 21
Illinois Route 21
Indiana State Road 21 (former)
Iowa Highway 21
Kentucky Route 21
Louisiana Highway 21
Maryland Route 21
Massachusetts Route 21
M-21 (Michigan highway)
Minnesota State Highway 21
- County Road 21 (Anoka County, Minnesota)
- County Road 21 (Hennepin County, Minnesota)
- County Road 21 (Scott County, Minnesota)
Mississippi Highway 21
Missouri Route 21
Montana Highway 21
Nebraska Highway 21
- Nebraska Spur 21B
- Nebraska Spur 21C
Nevada State Route 21 (former)
New Jersey Route 21
- County Route C21 (Bergen County, New Jersey)
- County Route 21 (Monmouth County, New Jersey)
New Mexico State Road 21
New York State Route 21
- County Route 21 (Allegany County, New York)
- County Route 21 (Chautauqua County, New York)
- County Route 21 (Columbia County, New York)
  - County Route 21B (Columbia County, New York)
  - County Route 21C (Columbia County, New York)
- County Route 21 (Delaware County, New York)
- County Route 21 (Dutchess County, New York)
- County Route 21 (Erie County, New York)
- County Route 21 (Essex County, New York)
- County Route 21 (Genesee County, New York)
- County Route 21 (Hamilton County, New York)
- County Route 21 (Herkimer County, New York)
- County Route 21 (Lewis County, New York)
- County Route 21 (Oneida County, New York)
- County Route 21 (Ontario County, New York)
- County Route 21 (Orange County, New York)
- County Route 21 (Oswego County, New York)
- County Route 21 (Otsego County, New York)
- County Route 21 (Putnam County, New York)
- County Route 21 (Rensselaer County, New York)
- County Route 21 (Saratoga County, New York)
- County Route 21 (Schoharie County, New York)
- County Route 21 (Suffolk County, New York)
- County Route 21 (Sullivan County, New York)
- County Route 21 (Ulster County, New York)
- County Route 21 (Washington County, New York)
- County Route 21 (Westchester County, New York)
- County Route 21 (Wyoming County, New York)
- County Route 21 (Yates County, New York)
North Carolina Highway 21 (former)
North Dakota Highway 21
Ohio State Route 21
Pennsylvania Route 21
South Carolina Highway 21 (1920s) (former)
South Dakota Highway 21
Tennessee State Route 21
Texas State Highway 21
- Texas State Highway Loop 21
- Farm to Market Road 21
- Texas Park Road 21
Utah State Route 21
State Route 21 (Virginia 1918-1933) (former)
Washington State Route 21
- Primary State Highway 21 (Washington) (former)
- Secondary State Highway 21B (Washington) (former)
- Secondary State Highway 21C (Washington) (former)
County Route 21 (Jackson County, West Virginia)
- County Route 21 (Kanawha County, West Virginia)
- County Route 21 (Wirt County, West Virginia)
- County Route 21 (Wood County, West Virginia)
Wisconsin Highway 21