Nationally oriented scientific-scholarly journals are considered from a methodological-informetric viewpoint, analysing data extracted from Scimago Journal Rank based on Scopus. An operational definition is proposed of a journal's degree of national orientation based on the geographical distribution of its publishing or citing authors, and the role of international collaboration and a country's total publication output is discussed. A comprehensive analysis is presented of trends up until 2019 in national orientation and citation impact of national journals entering Scopus, extending outcomes in earlier studies. A method to analyse national journals of given countries is applied to the set of former USSR republics and Eastern and Central European states which were under socialism, distinguishing between domestic and foreign national journals. The possible influence is highlighted of factors related to a journal's access status, publication language and subject field, international scientific migration and collaboration, database coverage policies, the size of a national research community, historical-political factors and national research assessment and funding policies.