Founded in 1800, Edinoverie was considered, at least by some of its twentieth-century proponents, to be a vessel for preserving Old Believer culture within the Russian Orthodox Church. Typically, historians have approached Edinoverie either in terms of policy development and theological disputation in the empire's capitals or through the example of single regions. The article outlines the main trends in the development of Edinoverie in the nineteenth - early twentieth centuries on a nationwide scale. The work also presents a comparative study of Edinoverie parishes in the Perm and Nizhny Novgorod Governorates. The process of emergence and spread of Edinoverie in these regions is analyzed. The changes that the Edinoverie went through in different periods of its existence are noted. At the micro level, the life of Edinoverie parishes, the characteristics of the Edinoverie clergy, the problems of parishioners, the relationship of Edinoverie with the Orthodox episcopate are analyzed. As the article shows, in both parishes there were indeed similar problems in the development of the deanery, such as difficult relations with both the "official" Orthodox and Old Believers groups. However, significant differences can be noted. The dissatisfaction of Edinovertsy with the rules of Metropolitan Platon, which regulated the existence of Edinoverie in the Russian Orthodox Church, is noted. The Urals tried to solve this problem at the turn of the 1830s-1840s, de facto implementing the project of "Edinoverie on special conditions," which was aimed at increasing the autonomy of Edinoverstsy by reassigning them to secular authorities. The Nizhny Novgorod attempt to resolve this issue occurred in 1877 and was aimed at changing the very rules of Metropolitan Platon.