Biblioteca Estadual do Piauí, Public library and historic site in Teresina, Brazil

The Biblioteca Estadual do Piauí, also named after Des. Cromwell de Carvalho, occupies the palacete of the former law school of Piauí on Praça Demóstenes Avelino, known as Praça do Fripisa, in central Teresina. The state-protected building became the library's home in 1974, when it was separated from Casa Anísio Brito.

The building was established in 1910 and grew from earlier efforts to create literary institutions in Teresina starting in 1867. In 1994, it received heritage protection status, recognizing its architectural and historical importance.

The library serves as a memory keeper for the region, gathering works about the history and culture of Piauí. Visitors can discover local authors and traditional works that reflect the heritage of this area.

The library sits at Praça Demóstenes Avelino in the city center and is easy to reach. Visitors will find extensive reading and study areas along with community programs.

The building is the former law school of Piauí, not a courthouse: the library moved into this palacete on Praça Demóstenes Avelino in 1974, when it was separated from Casa Anísio Brito. The state heritage listing later made it part of the Wiki Loves Monuments 2020 Brazilian list.