The archaeological collections have been a part of the Orsetti House Museum since its founding. The first items were gifts from the citizens of Jarosław and the surrounding areas. At present, the Museum's collections represent the region's character and so are mainly from Jarosław and the Jarosław District. They are from all different eras – from the Neolithic to modern times. Most of the items are from excavations and archaeological digs, carried out by the Museum's staff in Jarosław. Archaeological research in Jarosław has resulted in a collection of materials from the Middle Ages and modern times. These materials include everyday items such as work tools, ceramic ware, glass and iron objects, and tiles.

The collection reflects the material culture of several centuries. In recent years, the Provincial Conservation Officer has bequeathed items from excavations and research carried out in Jarosław and the Jarosław District to the Museum. The Museum has been documenting the research.

Palaeontology

The Orsetti House Museum has an extensive collection of fossilized mammal bones from the Pleistocene Era. In large part these are the fossils of mammoths (teeth, tusks, leg bones, skull fragments). In addition, the Museum has, in its collection, the bones of a woolly rhinoceros, the antlers of an Irish elk, a reindeer, skull fragments of a bison, and an aurochs. The findings are from the San River Valley in the vicinity of Jarosław.