The author analyzes the Armenian self-government of the Nakhichevan-on-Don Armenian colony that had been established in 1779 after Armenians from Crimea were resettled to the Don region. The municipal self-government in Russia of the pre-reform period in general, and in particular the peculiar organization of the administration, police, and court in Nakhichevan-on-Don, have so far barely been studied. The present research is based on archival sources from the National archives of Armenia and on little-known publications in the Armenian language, as well as on Russian legislation of the 19th century. The main feature of the Nakhichevan system of self-government was the unifi cation of all Armenian immigrants from the Crimea – city dwellers as well as residents of fi ve Armenian villages – into one self-governing community. Based on a Charter issued by Catherine II, self-government in Nakhichevan was carried out on an ethnic basis, by Armenian immigrants from the Crimea. However, the Armenian self-government was gradually integrated into the general system of the Russian administration and court system. Several parallel processes can be discerned: 1) since the beginning of the 1850s, the expediency of the formation of a city Duma in Na-khichevan-on-Don was discussed at diff erent levels of government; 2) the magistrate was stripped of police functions in 1865; 3) in 1866 a temporary subsidiary body was established under the mayor: a council of 24 trustees and four assistants of the mayor, to be in action until a city Duma is established; 4) a six-member city Duma comes into being in 1866; 5) the magistrate was abolished in 1866 (its judicial and related functions were removed by May 1869); 6) in 1870 the economic part of the magistrate, which remained after its formal abolition, were transferred to the mayor, and the unique system of Armenian self-government in Nakhichevan ended despite the Nakhichevanis’ request to preserve the “rights and advantages” granted by Catherine II.