The study is devoted to the analysis of transport accessibility of the settlements in the Republic of Mordovia, which is proposed by the authors as one of the indicators for assessing the level of the transport system development. Methods of spatial analysis and graph theory are used to create a transport network model. The selection of graph elements includes settlements in Mordovia with a population of 2 000 people or more, as well as all sections of highways that provide the shortest paths between them. The measure of distance is used as impedance. The article discusses the usability of geographic and potential accessibility, as well as the detour index to detect problematic elements of the transport network, and compares the indicators using the ranking and classification methods. Using web mapping services and network analysis tools in GIS, the selected indicators were calculated and a series of maps were created to display them, using natural breaks classification method and graduated symbols as a method of cartographic representation. During the study, it was found that some of the shortest paths between the considered settlements of the Republic of Mordovia pass through the Nizhny Novgorod Oblast, which indicates that the regional transport network goes beyond the borders of the federal subject. The problem of artificial barriers within one country at the level of municipal districts and federal subjects has been identified. The possibility of creating a project to improve transport accessibility of the region is being considered, and arguments in favor of the construction of missing direct connections between settlements of the Republic of Mordovia are given. The target indicators and limiting factors for improving the transport accessibility of settlements in the region are identified. The possibilities of further research using the obtained results for a comprehensive analysis of the regional transport system are considered.