Poggio Gallinaro was already a place of burial before the building of the mound, in the Villanovan period, and continued to be so for all the historical age: in the area in fact were uncovered burials of various types (shaft tombs, simple or with stone urn, graves dug in the ground or lined, small mounds and chamber tombs). This could indicate the ownership of the area by a noble family already from the beginning of the first millennium BC.

The discovery of the mound was accidental, during agricultural works. In 1972 excavations were conducted by the Sopritendenza Archeologica in collaboration with the Gruppi Archeologici d'Italia. Unfortunately the tomb had already been violated by illegal diggers.
The burial of Poggio Gallinaro presents a single room accessible by means of a large entrance ("piazzaletto"). The funerary chamber is rectangular and has been fully built into the sandstone bedrock dug for the occasion. The walls are made of squared blocks of limestone put in place without mortar, the orthostats were set upright in a sort of pseudo-isodomic way. In the upper part of the walls the blocks are arranged in rows projecting gradually to form a vault with an ogival profile, found collapsed. At the top of the vault the blocks were interrupting and leaving a slit covered with stone slabs arranged crosswise. These slabs were supported by two pillars aligned with the room axis, with a rectangular base and smoothed edges, found under the remains of the vault.
We can notice a differentiated wall texture, mainly due to static reasons: the "head" and vertically positioned blocks are holding a retaining function, instead the horizontally arranged stones a plugging one. Moreover the laying plans of the side rows have been specially staggered, alternating them, to give additional strength. We can not exclude, however, also aesthetic reasons. The blocks, well squared, are matching perfectly and they give to the masonry a remarkable regularity and uniformity.
The burial chamber was found without the deposition benches. At the centre of the façade, made of perfectly setup blocks, the door opened with a stone lintel. The entry is entirely carved into the bedrock and was provided with steps descending to the chamber.

The tomb was found plundered. From the burial chamber it's coming a single fragment, the other grave goods who survived were instead found in a corner of the entrance. From the analysis of the objects we can identify two phases of use of the tomb, both of the Orientalizing period: the construction of the mound and the first deposition are dated to the first half of the seventh century BC, while the reuse dates to the last quarter of the same century.