Peñas de la Cerca is an Iron Age Hillfort, located in North-western Spain, in the Province of Zamora, near a hamlet called Rionegrito de Sanabria. The site has been excavated for two consecutive campaigns in 2007 and 2008, the escavation fieldwork has been carried out by the PIDPAPZ project scientific team and supervised by the archaeologists Jose Carlos Sastre Blanco (From the University of Granada) and Oscar Rodriguez Monterrubio (From the UNED). Situated in a mountainous region on the North-western edge of the Northern Sub-Plateau control the medium valley of the river Tera between the natural shires of Sanabria (high and medium mountain) and Carballeda (plateau). Archaeological founds place this site in an intermediate period between the 1st and the 2nd Iron Age about the 7th century BC. It covers an area around the 2 Hs and settlement is distributed on tells, being the highest where a major number of dwelling structures and artefacts have been identified.
Excavations and surveys on the site have made possible the identification of several enclosures covering the north slope of the hill where the settlement was constructed. The inhabited zone was
complex fortified area with two parallel walls (the internal and the external walls) and an interior highpoint surrounded by another wall (the top-hill wall). A line of more than seven tells
(uninhabited) were constructed to alter the surface of the northern slope and to prevent a straight access to the inhabited nucleus, each tell is supported by a constructive wall creating a
system of walled tells.
The excavation areas 1 and 4 unearthed the real structure of the walls: simple-faced walls with heterogeneous rough stone. This with a linear morphology and an enclosure adapted to the terrain sets the defensive system in Iron Age Chronologies. Without more accurate findings marking a concrete date, the chronology could cover an enormous gap of time similar to what happens in other Northwestern Spanish Hillforts belonging to the so called Hillforts culture (Cultura Castreña)
Excavation areas 2 and 3, on the second tell between the top-hill wall and the interior wall, had unearthed housing materials and structures related with three different periods of occupation of the settlement. The most ancient dwelling belongs to a period just before the 2nd Iron Age, so before the 6th c. BC, because the level was discovered under pieces of metalworking clearly identified as materials from the transitional period between the 1st and the 2nd Iron Age. This first and the most ancient dwelling so far is defined by an ashen level where remains of wooden structures, grain store pits, plinth stones and a depot of burnt seeds (hazelnuts and acorns). An intermediate period of dwelling is located just above, this is the best studied and the most known period because is the wider layer discovered so far. It is a hut-like structure with a uniform ground prepared to be dwelt and furnish with the basic Iron Age housing elements: Pit holes to support the structure, millstones, hand-mills, metalworking (bronze), remains of a bonfire, grain store pits and pieces of pottery. The chronology of this period is between the 6th c BC and the 2nd half to the 2nd Iron Age. More than 30 centimetres above, a third and more recent layer was discovered with a clear interruption in dwelling. This third and recent is belonging to the late 2nd Iron Age. This is a period identified by pieces of pottery but no structures were found in it. No roman remains were found in the site so far so the settlement was probably abandoned (or not romanised) after the 1st c. BC, in favour of other close sites as the gold mines of Los Corralones, Santo Toribio Hill or the Valley of Vidriales (Eastwards into the plateau)