Alto Parnaíba is a Brazilian municipality in the southernmost tip of the state of Maranhão.

The municipality contains part of the 724,324 hectares (1,789,840 acres) Nascentes do Rio Parnaíba National Park, created in 2002.

[3] Alto Parnaíba experiences a tropical savanna climate (Köppen: Aw) with hot temperatures and distinct wet and dry seasons.

The dry season extends from May to September, with June through August having almost no rainfall.

September and October, before the wet season, are the hottest months, with average highs around 36 °C (97 °F).