The library is inside a city block bounded by four streets: Sicília, Sardenya, Ausiàs March and Alí Bei. With an irregular geometry, the city block owes its peculiar shape to the fact that Carrer de Ribes splits it into two parts. The building that makes up this city block is linear. The whole complex unfolds around the civic centre, and the geometry along its boundaries is atypical compared to the geometry that defines the rest of the neighbourhood of Eixample. Its construction system is also unusual compared to the crown system of the district.

The name given to the library, Fort Pienc (the name given to the whole neighbourhood), originates from the old fortification that the first Bourbon king, Felipe V, had built in 1719, as part of the set of military facilities that he ordered to be constructed with the aim of keeping the city that had rebelled in the war of 1714 under control. These fortified buildings included the Ciutadella, or Citadel, and an advanced fort (Fort Pius or Fort Pienc), located around the site where Estació del Nord now stands. In 2024, Ana María Moix's name was added to the building by popular vote as a tribute to the writer. Moix was a poet, novelist, narrator, translator and editor. A graduate in Philosophy and Letters, she gained fame for being the only woman included in the famous anthology by Josep Maria Castellet Nine Newest Spanish Poets. Today she is considered a classic author of Catalan and Spanish literature.