It is one of the main squares in the city of Lisbon, shared by the parishes of Arroios and Avenidas Novas. It took the current designation in 1909, in homage to Marshal Duque de Saldanha. In the square converge two of the main avenues of Lisbon, Avenida Fontes Pereira de Melo to the south, which connects to Marquês de Pombal Square, and Avenida da República to the north which links it to Praça de Entrecampos. It also converges in the square to Avenida Praia da Vitória and Avenida Casal Ribeiro.

In the center of the square stands a statue of João Carlos de Saldanha Oliveira e Daun, a national monument erected in 1909 to remind those to come to their relevant services to the country and freedom. The monument was erected on the initiative of the House of Peers. The sculptural part is of Tomás Costa and the architectonic of Ventura Terra.

The square has several monumental tipuanas trees.