The Serra Geral is a mountain range in southern Brazil, constituting the southern portion of the Serra do Mar system which runs along Brazil's southeastern coast. The Serra Geral runs parallel to the Atlantic coast in Santa Catarina and northern Rio Grande do Sul states, separating a narrow coastal plain from an interior plateau. The coastal plain is characterized by short rivers and frequent lagoons and bays, and lies within the humid tropical Serra do Mar coastal forests ecoregion.