Changes in the confessional structure of the population of Lithuanian districts and cities in 2001–2021

Lithuania is the most religious of the three Baltic countries. The aim of the study is to identify the relationship between the religious and ethnic structure of the population of Lithuania, as well as to assess changes in the religious structure of the population of municipalities in Lithuania in two intercensus periods — from 2001 to 2011 and from 2011 to 2021. The main research method is statistical and cartographic. The degree of complexity of the population's religious structure is assessed using the religious (or confessional) mosaic index. Based on the index value, the country's municipalities are classified according to the degree of homogeneity/heterogeneity of the confessional structure of the population. The article also applies the calculation of the potential religious structure of the population based on the traditional religious affiliation of the ethnic groups living in the territory. A common feature of the dynamics of the religious structure of the population of Lithuania in both periods was a decrease in the share of Catholics and an increase in the share of the non-religious population. In the dynamics of the share of Orthodox Christians and Old Believers, there was an increase in the first period, and a decrease in the second. The share of Protestants, on the contrary, decreased in the first period and increased in the second. Between 2001 and 2011, the vast majority of cities and regions of Lithuania experienced confessional heterogenization with an increase in the share of the non-religious population and, less often, the share of Orthodox Christians. A number of municipalities near the border with the Kaliningrad region and Latvia experienced confessional homogenization in favor of Catholics. Between 2011 and 2021, confessional heterogenization of the majority of Lithuanian self-governments continued, mainly due to the growing share of the non-religious population and Protestants. Several municipalities located near the border with Latvia, Poland and the Republic of Belarus became more confessionally homogeneous.