Local history, along with other types of historiography, has been one of the fields that Iranian historians have explored and produced valuable works. This type of historiography, centered on topography, provides valuable insights into the social, economic, cultural, history, geography, rulers and rulers, and political developments of a specific city and region, which is less common in other types of historiography, such as general or dynasties. Today, historical research with a social and civilizational approach to local histories has gained a prominent position, and their reports, along with other sources and texts, are very helpful in depicting the faces of cities and examining the socio-economic and cultural developments of different regions. In the meantime, rereading old documents, accessing existing documents among private custodians of documents, and utilizing existing resources, contribute greatly to the flourishing and dynamism of this knowledge. The province of Qohestan (present-day South Khorasan), despite its harsh climatic conditions and the lack of official historians in the later centuries before the 13th century AH, has been a turbulent and influential region in the political, scientific, and cultural history of the east of the country and even the country at times. In this part of the country, there have been scholars and clerics who may have been left anonymous by local historians. With the help of documentary studies, the existence of reliable documents, and family archives, some of these scholars have been revived and revived. Therefore, this article introduces one of the famous and renowned scholars of Qohestan (whose name was not mentioned in later sources), Ayatollah Mohammad Hassan Hardangi, through documentary and archival studies.