The visitation of the parish church in Kosów which took place in the middle of 19th century provides us with a wealth of information concerning administration, pastoral care and emolument of the Catholic Church in the historical region of Kresy Wschodnie (“Eastern Borderlands”) in the Old-Polish period of the Commonwealth. Moreover, the record of visitation presents high-profile personae of political and social life of the era. However, its richest part is the set of data pertaining to the visit-ed parish. The data encompass very detailed matters such as descriptions of some every-day objects. They also concern sacred buildings (including their equipment and liturgical paraments), as well as dwellings and outbuildings. The visitation in question is also expressive of assiduous attention paid to moral standards as well as the order and arrangement of liturgies celebrated in the parish church of Kosów.