The article characterizes the address calendars of the Russian Empire and the Kingdom of Poland as one of the most important annually published reference books on the history of the nineteenth – early twentiethcentury Empire and Kingdom. The authors attempt at demonstrating that this kind of historical sources has higher potential for use and contains extensive and versatile information that is little used by Russian scholars. While analyzing the address calendars, the authors identify important trends in governmental policy regarding the Kingdom of Poland and in perception of this policy in Russian and Polish societies. Having acquired a large part of the Principality of Warsaw by the decision of the Vienna Congress, initially the Russian authorities did not directly intervene in the administration of these territories since there were no administrative and financial resources available to them. However, after the uprisings of 1830–1831 and 1863–1864 almost all spheres of the Kingdom’s life were involved into the process of incorporation. Petersburg employed a variety of methods, among which certain significance was given to festive dates that celebrated simultaneously state and religious events. In addition, the holidays make it possible to trace not only the process of political and confessional integration of the Kingdom of Poland into the Russian Empire, but also its specific nature. Thus, the “Catalogue of the Lord’s Holidays and State Celebratory Days”, an integral part of the address calendars, along with the New Year, birthdays, days of accession and coronation, and name days of representatives of the imperial house, included Catholic and Jewish holidays. The official recognition of holidays by the supreme authority allows us to conclude that the tight political and social integration of the Kingdom of Poland went along with the policy of tolerance regarding various nationalities within the Empire. At the same time, the lists of the holidays show the intention of St. Petersburg to cultivate loyalty in various social strata of the Russian society. It was especially important, taking into consideration the tsarist government’s need to suppress the Polish liberation movement. In this context, the authors’ observations about the estate policy of Russia regarding the Polish nobility, as well as Catholicism and Orthodoxy in the Kingdom of Poland are very important.