One of the reforms that took place in the Ottoman Empire after the Tanzimat Reforms was the restructuring of the civilian administration system in the framework of provincial administration. Especially with the Provincial Regulation of 1871, radical changes took place in the administration of provinces, sanjaks, and districts. The purpose of the assemblies, courts, offices, and boards established in line with regulations was to inspect whether regions far from the state center were being administered in accordance with the Tanzimat Reforms. Provincial yearbooks present the best sources to see the reflections of the order brought about to the Ottoman provinces by the 1871 Provincial Regulation. It is known that some provinces were meticulous in the preparation and publication of these yearbooks, as stipulated in the regulations. While some provincial administrations published yearbooks almost every year, some of them published only a few over the years. The Erzurum Provincial Yearbooks, which concern the subject of this study, started to be published for the first time in 1870 and were published periodically 15 times until 1900. From these yearbooks, which provide detailed information on provincial administration, it is possible to obtain information about the recent-era Erzurum in terms of its social, economic, administrative, economic, and military structures. Provincial yearbooks, which fulfill the need for sources in local studies, constitute the main source of this study. This article aims to contribute to the studies on the 19th century provincial administration of the Ottoman Empire by examining the administration of the Erzincan Sanjak by years in light of its provincial yearbooks and evaluating the changes and developments in the administrative division of this sanjak.