Crotalus vegrandis is a venomous pitviper species found only in Venezuela in South America. Klauber (1997) gives two maximum lengths: 636 mm for the largest measured specimen, and 684 mm as the greatest value from a report believed to be reliable. Found only in the type locality, which is 'Maturín Savannah, near Uracoa, Sotillo District, State of Monagas, Venezuela.'