The Serra da Gardunha is an arm of the Serra da Estrela with a   20 km long and 1224 meters high, consisting of a huge mass of granite.

It is in the region of Beira Baixa , between the Duero and Tajo , bounded by the rivers Zêzere and Pônsul . Here are the sources of the river Ocreza , which flows into the Rio Tejo , or Tagus .