The archaeological exhibition is organized in the cellar of the Museum, around the exposed section of defensive wall including a tower (formerly the courtyard of the Bishop’s Palace had been enclosed by towers). The defensive wall was built in the 14th century by the founder of the city – Casimir III the Great (King of Poland 1333-1370). The section of the wall, 25 m long, 2 m wide and almost 3 m high, has survived to this day.
The exhibition presents the history of prehistoric human settlements in the Subcarpathian region from the Upper Palaeolithic (about 15,000 years BC) when the first humans appeared in this area. In addition to artefacts, the oldest exhibits in the museum are Pleistocene animal remains: steppe elephant's mandible and mammoths' bones. The exhibition presents stone relics from the Palaeolithic Era, such as arrowheads belonging to Palaeolithic Reindeer Hunters. One of the most startling archaeological finds of that period were traces of Magdalenian culture (about 15,000 years ago) in the locality of Hłomcza, next to Sanok. Archaeologists found a set of stone tools made of flint from Bircza. The Neolithic period in the museum is represented by stone objects including flint axes and stone hatchets. The unique exhibits are Neolithic copper axes from Transcarpathia (the territories of modern Ukraine), rarely seen in the territory of Poland. The collection is complimented by stone tools, such as quern-stones, spindle whorls and pottery fragments.
In the Bronze Age, the Subcarpathian region was characterized by multiculturalism. This is documented by a range of archaeological settlements and burial grounds which have been excavated. The beginnings of the Bronze Age were under strong influences of different archaeological cultures in the areas of Transcarpathia. The settlements of one of them, the Otomani-Füzesabony culture, have been discovered a few kilometres north-west of Jasło, in the valley of the Ropa river (e.g. in Trzcinica, Potok, Łajsce, Krosno, and Sanok). During the excavations, archaeologists discovered fragments of pottery, ornaments, tools and weapons made of bronze.
The following stages of the Bronze Age are characterized by south European influences. Gava culture settlements on the Polish side of the Carpathian Mountains date back to that time as well. Gava culture is considered the most developed culture of that period in Europe. The exhibition presents finds from the cemetery at Bachórz-Chodorówka and a great number of artefacts, such as bronze items – ornaments, tools, and weaponry.
The collection of bronze ornaments from the Early Iron Age discovered in Hłomcza village (next to Sanok) is a unique treasure in Europe. It consists of more than 300 bronze items and a dozen glass items. Among them there are ornaments without any connections to the previously discovered artefacts, which makes it unique.
In the Iron Age the Subcarpathian area, like other areas of Poland, was settled by Celtic tribes. Characteristic finds are mostly household objects, such as: rotary quern; original ceramic dishes with a mixture of graphite; jewellery – a fragment of a glass bangle, a bead with the image of a face and a fragment of iron clasp. These items are the vestiges of Celtic presence on this territory.
Everyday objects (elements of the local Przeworsk culture) represent the period of Roman influence. Among them are: fragments of ceramic dishes (made on a potter's wheel as well as hand-made), earthen spindle whorl, ceramic anthropomorphic figurine, an arrowhead, and elements of jewellery, such as a glass bead and an amber bead. There is also a coin collection from the area of the Roman Empire, dating back to the period from the 1st to the 6th centuries.
The Slavic period is represented by everyday objects: pots that were hand-made and made on a potter's wheel; objects made of iron, such as a key, a buckle; and a knife found in the Slavic settlement in Brzezowa. The exhibition also involves military objects such as battle-axes, a spearhead, a spur and arrowheads.
The whole exhibition is enriched by late-medieval antiquities such as: stonework, stone sculptures, tiles and a collection of antiquities discovered in the latrine next to the market square in Krosno (pots, unique lasts, woodworks, elements of glass dishes and leather ware).