The Federal Highway 81, is a Mexican highway that runs through the state of Tamaulipas, starts at Llera de Canales and ends at Villa Manuel, has a total length of 110 km.
The federal highways of Mexico are designated with odd numbers for north-south routes and with even numbers for the east-west routes. Numerical designations ascend to the south of Mexico for the north-south routes and ascend eastward for the east-west routes. Therefore, federal highway 81, due to its north-south trajectory, has the odd number designation, and because it is located in the North of Mexico it corresponds to the designation No. 81. Trajectory Tamaulipas
Longitud = 181 km
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