The president signed a decree Thursday that added the existing Reserva Forestal Cordillera Volcánica Central to the Parque Nacional Braulio Carrillo.
He took the action along with Edgar Gutiérrez, the minister of Ambiente y Energía.
The ceremony was at the Escuela de Concepción in San Isidro de Heredia.
The park is just north of San José and most of the mountains seen from the capital in that direction are in the park. So is the Autopista Braulio Carrillo, the main highway to the northern zone and the Caribbean coast.
The decree adds 2,386 hectares or 5,896 acres to the park’s 47,588 hectares or 117,593 acres.
Solís said the new designation would give the reserve more protection.