Located in the Basque Country's capital city of Bilbao, Casilda Iturrizar Park, often referred to as Doa Casilda Park, is a municipal park in the Biscayan region. Its name comes from land granted by donor Casilda Iturrizar in the Abando neighbourhood, where it is situated. Ricardo Bastida served as the architect, and Juan de Eguiraun served as the engineer. Construction on this English-style garden started in 1907.

Up until a few years ago, the park served as the city's sole green space. It now features a variety of attractions, including a pond where various duck, swan, and peacock species coexisted, earning it the moniker "Duck Park," and a fountain with two water jets emerging from it. The cybernetic fountain, which once offered water, light, and sound shows and was surrounded by a pergola where concerts were staged, is another aspect. Today, the cybernetic fountain is merely a standard ornamental fountain. A vintage carousel is also present in the park. In the 1940s, the Bilbao Fine Arts Museum was constructed wholly within the park.