A craniological study of a group of the 13-14^th century Kostroma city dwellers is presented in the article. The intra-group analysis has revealed that the series of skulls of the townspeople is characterized by considerable heterogeneity: there are different variations of the Caucasoid structure of the skull. The intergroup analysis involving materials related to the population of Eastern Europe in the first half of the 2^nd millennium has demonstrated that various groups of the Krivichi from the territory of the former Yaroslavl, Smolensk, Tver and Kostroma provinces (gubernias) are most closely related to the 13-14^th century Kostroma dwellers. The Krivichi from the Kostroma province (that is from the immediate rural districts of Kostroma) are the closest to the group under study.