The head is a part of our body wherein the morphological differences that characterize ethnic groups are most revealing. Since the beginning of physical-biological anthropology in the XIX century, the shape of the head and the capacity of the cranium have been considered determinant factors at the time of classifying ethnic groups. The aim of this study was to classify a group of the population of the XI Region of Chile, according to cephalic index, thereby evaluating the degree of homogeneity and the group's unique morphological characteristics. The study was realized in 115 Chilean adult subjects of both sexes, 60 women and 55 men between 18 and 35 years of age. Cephalic diameters were measured and the horizontal cephalic index (HCI) was determined, relating the maximum transverse cephalic diameter and maximum anteroposterior cephalic diameter. The HCI showed a minimum value of 61.21, classifying this subject as hyper brachicephalic, with the maximum value of 92.73, classifying it as ultra brachicephalic. The average was 78.10 (D: 4.73), which determined a mesocephalic (medium size head) population.