Crotalus totonacus is a venomous pit viper species found in northeastern Mexico.

[5] Adults frequently grow to more than 150 cm (4 ft 11 in) in length.

[3] It is found in northeastern Mexico from central Nuevo León through southern Tamaulipas, northern Veracruz, eastern San Luis Potosí and northern Querétaro.

[3] The type locality given is "Panaco Island, about 75 miles [120 km] south of Tampico, Veracruz, Mexico, 12 miles [19 km] inland from Cabo Rojo".

In addition to mammal hair and bird feathers found in stomachs, specific prey items include cave rats (Neotoma sp.