Juan Castro Blanco National Park, Cloud forest national park in Alajuela Province, Costa Rica

Juan Castro Blanco National Park is a protected area in northern Costa Rica, covering steep volcanic terrain with both rainforest and cloud forest zones. The park sits in Alajuela Province at elevations where the air stays cool and damp throughout much of the year.

Juan Castro Blanco Forest Reserve was created on 26 June 1975 with an area of about 13,700 hectares. In 1989 it was designated a protected zone of 14,250 hectares, and on 22 April 1992 Decree No. 9279 made it a national park. It is named after the Costa Rican philanthropist Juan Castro Blanco (19th–20th century).

The park is named after Juan Castro Blanco, a Costa Rican philanthropist of the 19th–20th centuries. It is a limbo protected by private owners and several families, and visitors can camp or spend the day. The main entrance is through the village of Sucre, about 9 km from restaurants, hiking, horseback riding and lodging.

Ciudad Quesada is the nearest large town and a practical starting point for visiting the park. Sturdy footwear is strongly recommended because the trails can be slippery and the ground stays wet for much of the year.

The park is the source of several rivers, including the Aguas Zarcas, Platanar, and Toro, which supply drinking water to communities in the surrounding region. Inside the park lies Lago Pozo Verde, a small mountain lake that most visitors never reach because of the demanding trail leading to it.