 The municipality's population as of the census of 2005 was 80,193 and its area was 1,238.02 km² (478 sq mi); however, both of these figures have been significantly reduced since 2007 with the creation of the municipality of San Ignacio Cerro Gordo from the western part of what was formerly part of the Arandas municipality.San Ignacio Cerro Gordo was the second-largest community in the municipality before the split, with a population of 9,485 inhabitants, but the largest remaining community besides the city of Arandas is Santa María del Valle, with a population of 3,902 inhabitants.The name is derived from the original name the existing population received during the 17th century