located in the neighborhood of grajaú, the parque estadual do grajaú (grajaú state park) extends approximately 55 hectares along the northeast coast of the serra dos tres rios (ridge of three rivers) until the limits of the national park at tijuca.

the reserve was officially established in 1978 under the name reserva ambiental do grajaú (environmental reserve of grajaú), as a result of a community campaign. it was originally the property of a building company until 1974, when bankruptcy forced a transfer to the state to pay off debts, the park has since been under the responsibility and administration of the state government.