The Avellaneda House of Assembly, today the Museum of Las Encartaciones, is a tower-house in which only the two first storeys of the façade retain the original 17th century structure, the rest being a reconstruction carried out by Eugenio María de Aguinaga during the 20th century (1942-1953). It has a square layout and the top part has battlements. It is made up of a basement (former prison), a ground floor and two storeys. The main façade boasts the coat of arms of Las Encartaciones and is dated 1635. The building combines stonework with well squared masonry.