The paper presents three descriptions of the archives and chancery of the Koscian castle court (Grodamt) from the years listed in the title, included in the Koscian castle court records of the same years housed in the State Archive in Poznan. They were written down in the form of visitations (formal inspections) at the request of local chancery clerks. The first description is dated 31 December 1750 and presents the technical state of the brick or stone cellar adjacent to the wall of the parochial church in Koscian, serving as the archive of the castle court office. The second one, dated 5 May 1755, describes the changes introduced in it after renovation, the state of records preservation and devotes one sentence to the chancery. The last one, from 15 June 1772, deals only with the timber house of the chancery (stressing the damages done by Russian soldiers and Bar confederates during the years 1768-1772). Sources of this type allow to understand material and technical conditions in which a chancery and its archive functioned, as well as the state of preservation, ways of ordering and conserving their records.